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February 2012
Articles
February 2012 [6(2) 2012]
Table of Contents
February 2012 [6(2) 2012]
Table of Contents
An intelligent approach based on adaptive neuro-fuzzy inference systems (ANFIS) for walnut sorting Smail Khalifa, Mohammad Hassan Komarizadeh Abstract In the present paper, an efficient walnut recognition system was developed by combining acoustic emissions analysis, Principle Component Analysis (PCA) and Adaptive Neuro-Fuzzy Inference System (ANFIS) classifier. The system was tested later and classified walnuts into two classes. In order to produce sound signals, a 60o inclined polished steel plate was used. This intelligent system had three phases (stages). In pre-processing phase, the data acquisition and pre-processing for impact signals performed and 281 sample data were used to evaluate the performance of the system. In feature extraction stage, some statistical parameters of impact signals in the time domain were selected as a feature source for sorting, and then the feature reduction was carried out using PCA. In classification phase, selected statistical features were used as the input of the ANFIS classifier. The classification accuracy of proposed PCA-ANFIS intelligent system was 100%. Pages 183-187 | Full Text PDF |
Application of a spectral sensor for the assessment of nitrogen content in lettuce plants M. Maleki, J. Massah, M. Dehghan Abstract Nowadays, current heavy reliance on agricultural chemicals has raised many environmental and economic concerns. Therefore, farmers need to find a way for optimal application of agricultural chemicals. Nitrogenous compounds are the most important items for the growing crops. In this research, a nitrogen sensor was developed to assess nitrogen status of lettuce plants. For this purpose, a spectral sensor (TCS230, TAOS, USA) along with an AVR microcontroller (ATmega32, Atmel, USA) (620-700 nm) was used. Moreover, the SPAD test on the leaves of lettuce plants was preformed to compare and confirm the results. The results showed that intensity of solar influence on the sensor and the light source can be fixed by this approach. Spectral sensor were found to be linearly correlated (r2=86) with chlorophyll content and sensor data. In addition, it was found that the distance between leaf and sensor is very important, where the best results were obtained within 1-3 cm. The increase of distance over 8 cm created a lot of meaningless data. Data analyses showed a correlation between sensor and chlorophyll meter as r2=0.22. Results shows that the sensor used in this research have better performance than leaf color chart. In addition, commercial sensors have better performance compared with the sensor used in detection of nitrogen plant content. Pages 188-193 | Full Text PDF |
Molecular diversity of Cumin (Cuminum cyminum L.) using RAPD markers Alireza Bahraminejad, Ghasem Mohammadi-Nejad, Mihdzar Abdul Kadir, Mohd Rafii Bin Yusop Abstract Cumin (Cuminum cyminum L.) belonging to the family Apiaceae is one of the oldest and economically most important medicinal spices. In this study, as a comprehensive research on genetic diversity, forty nine cumin ecotypes, belong to nine Iranian regional sub-populations were assessed using RAPD markers. DNA extracted from cumin seeds through CTAB method. Twenty three RAPD markers were used for diversity assessment, in which 21 showed polymorphism. Allele frequency and polymorphism information content (PIC) of each locus were calculated by Power Marker version 3.25. Molecular variability among and within populations was assessed accordingly. Based on molecular data, Jacquard’s similarity coefficient was used to detect the phylogenic relationship; subsequently dendrograms were drawn based on UPGMA using NTSYS software. Cluster analysis among the populations categorized nine populations into two groups at the similarity level of 0.43, in which class one was consisted of only Golestan population and the rest were arranged in the second group. Golestan and Northern-Khorasan populations showed the highest difference while Kerman and Esfahan populations showed the most similarity. Based on Principal Coordinate Analysis (PCOA), 79% of variation was explained by two first principal components. Populations of Semnan, Yazd and Golestan showed different reaction rather than the other populations. It is suggested that Kerman, Esfahan and Southern-Khorasan may have the same ancestors. Molecular diversity among 49 ecotypes, as the sub-populations of nine populations derived from different Iranian states, showed five different categories. Based on the result it can be concluded that there is a high potential of variability in Iranian cumin populations which are very important sources for cumin breeding objectives. Pages 194-199 | Full Text PDF |
The interactive effects of water and fertilizer on photosynthetic capacity and yield in tomato plants Juanjuan Zhu, Yinli Liang, Yanli Zhu, Wanglin Hao, Xingjun Lin, Xing Wu, Anrong Luo Abstract An experiment was carried out with potted tomato (Lycopersicon esculentum Mill.) plants to investigate the interactive effects of soil moisture (low: 55% of field capacity [FC]; moderate: 75% FC; and high: 95% FC) and fertilizer application rates (low: N 0.187 g/kg + P2O5 0.131 g/kg + K2O 0.224 g/kg; high: N 0.267 g/kg + P2O5 0.187 g/kg + K2O 0.320 g/kg) on leaf photosynthetic pigments, gas exchange, chlorophyll (Chl) fluorescence, and fruit yield for the entire fruit growing season. The correlations among photosynthetic parameters of interest, fruit yield, and plant biomass were also analyzed. Results indicated that there were significant interactive effects of soil moisture and fertilization rates in tomato plants. Soil moisture had greater effects on fruit yield, plant biomass, and root/shoot ratio than did fertilizer rates. The high fertilizer rate decreased leaf photosynthetic pigment contents, gas exchange, and Chl fluorescence when soil moisture was 55% FC, but it increased those values when soil moisture was 95% FC. When soil moisture was 75% FC,the high fertilizer rate increased leaf photosynthetic pigment contents, decreased gas exchange, and had little effect on Chl fluorescence. Linear correlations between net photosynthesis rates (PN) and photosynthetic pigment contents (Chl a/b, carotenoids, Chl/carotenoids) and Chl fluorescence parameters (Fv'/Fm', FPSII, FPSII/FCO2, ETR, and Fv/Fm) were found. Leaf photosynthetic pigment content was positively related to dark-adapted Chl fluorescence (Fv/Fm) but negatively related to the ratio of the quantum yield of PSII to the quantum efficiency of CO2 fixation (FPSII/FCO2). PN was quadratically correlated with fruit yield, indicating that improving PN with in a suitable range could increase fruit yield for tomato plants. Pages 200-209 | Full Text PDF |
Drying of jujube (Zizyphus jujube Mill.) fruit: comparison of prediction from mathematical models and artificial neural networks Ali Motevali, Ahmad Abbaszadeh, Gholam Hassan Najafi, Saeid Minaei, Barat Ghobadian Abstract In this study, the application of artificial neural networks (ANNs) and mathematical models for hot-air drying of Jujube fruit is presented. Air velocity, temperature and drying time were used to predict moisture ratio (MR) and drying rate (DR) variations. Assessment of seven mathematical models revealed that the Midilli model exhibited the best performance in fitting the experimental data (R2=0.9996, RMSE= 0.005112 and ?2=2.61E-05). Using some of the experimental data, an ANN, trained by standard back-propagation algorithm, was developed. The ANN model was able to predict variations of MR and DR quite well with determination coefficients (R2) of 0.9997, 0.9993 and 0.9996 for training, validation and testing, respectively. The prediction mean square error was obtained as 0.001, 0.0011 and 0.0013 for training, validation and testing, respectively. Results show good agreement between the experimental data on the one hand and mathematical models as well as the ANN model on the other. However, neural network modeling yielded a better prediction of moisture ratio and drying rate of jujube fruit compared to all of the mathematical models studied. Pages 210-218 | Full Text PDF |
Vitrification and histological analyses of protocorm-like bodies of vanda kaseem’s delight orchid Ranjetta Poobathy, Nor’Ain Ahmad Hesam, Advina Lizah Julkifle, Sreeramanan Subramaniam Abstract This study was conducted to investigate the potential of cryopreserving protocorm-like bodies (PLBs) of Vanda Kaseem’s Delight Orchid using plant vitrification solution 2 (PVS2). Measured parameters included the effect of PLB size (1-2 and 3-4mm), the effect of sucrose preculture concentrations and duration (0.0, 0.10, 0.25, 0.50 and 0.75 M, for 24 and 48 hours), the effect of dehydration duration (0, 10, 20, 30 and 40 minutes) and the effect of various unloading periods (0, 10, 20, 30 and 40 minutes) on survival of cryopreserved PLBs, as assessed using spectrophotometric 2,3,5-triphenyltetrazolium chloride (TTC) assay at 490nm. The PLBs were also subjected to a histological study to observe differences in both cryopreserved and non-cryopreserved PLBs of the orchid. The best results in the cryopreservation of PLBs of Vanda Kaseem’s Delight was obtained when 3-4mm PLBs were precultured in VW medium supplemented with 0.1M sucrose for 24 hours, followed by a loading treatment, and 20 minutes of dehydration in PVS2 at 0°C, prior to cryostorage, and 30 minutes of unloading treatment after 90 seconds of thawing. Histological observations of cryopreserved PLBs indicated that most of the damages resulting from cryostorage occurred in the cell wall and nucleus of the cells. Pages 219-224 | Full Text PDF |
Effect of 6-Benzylaminopurine on flowering of a Dendrobium orchid Nisha Nambiar, Tee Chong Siang, Maziah Mahmood Abstract Dendrobium orchids are popularly used as cut flowers because they come in a wide range of vibrant colours besides being able to produce high number of flowers per inflorescence. There is a significant interest in developing methods to promote early flowering in commercial Dendrobium orchids. In this study, the potential effect of benzylaminopurine (BAP) on inducing inflorescence production of a Dendrobium hybrid (Dendrobium Angel White) was investigated. D. Angel White plantlets were subjected to spray containing different BAP concentrations. The results indicated that the application of BAP increased the percentage of inflorescence production, induce earlier flowering, and contributed to the differences in inflorescence length and the number of leaves and flowers produced. However, the application of BAP did not significantly influence the size of the flowers. This study showed that BAP is a potential plant growth regulator that can speed up the flowering process of D.Angel White. Pages 225-231 | Full Text PDF |
Leaf senescence and photosynthesis in foxtail millet [Setaria italica (L.) P. Beauv] varieties exposed to drought conditions Hui-Ping Dai, Chang-juan Shan, An-Zhi Wei, Tuxi Yang, Wen-Qing Sa, Bai-Li Feng Abstract In this paper, we studied the changes of net photosynthetic rates (Pn), the contents of chlorophyll, soluble protein, malondialdehyde (MDA), superoxide radical (O2-·), and hydrogen peroxide (H2O2), and the activities of superoxide dismutase (SOD; EC1.15.1.1) and catalase (CAT; EC 1.11.1.6) in the leaves of two foxtail millet varieties (05-61 and Jingu3) under drought stress from 14 days after anthesis to maturity. PN, the contents of chlorophyll and soluble protein and the activities of SOD and CAT increased and then declined as the plants aged, whereas the accumulation of MDA, O2-· and H2O2 gradually increased with senescence. Although the leaves of two varieties generally shared a similar pattern of senescence, their rates of aging differed. The activities of SOD and CAT in leaves of 05-61 declined more quickly than Jingu3, particularly in the late stages of grain filling. Taken together, the results implicated that the alleviation of leaf senescence played an important role in promoting grain filling and enhancing the yield and quality of 05-61 in the rain-fed agriculture area. Pages 232-237 | Full Text PDF |
Simulation of salinity distribution in the overlap zone with double-point-source drip irrigation using HYDRUS-3D Yuyang Shan, Quanjiu Wang Abstract Salinity is a serious and chronic problem for agriculture in arid and semi-arid regions. Drip irrigation is widely used in such regions because it can decrease salinity in the soil. With drip irrigation, there is a region of confluence between each pair of emitters, termed the overlap zone, in which plants are grown. Hence, knowledge of the salinity distribution in the overlap zone is important to achieve high crop yields. The salinity distribution in and around the overlap zone was investigated empirically and in simulation (using HYDRUS-3D) for double-point-source drip irrigation with different irrigation volumes (8 L, 10 L, and 12 L) and emitter spacings (30 cm and 40 cm) in a sandy soil near Korla in Xinjiang Autonomous Region. The predictions from HYDRUS were found to be very close to the observed data in terms of the coefficient of correlation (R2) and the root-mean-square error (RMSE). The R2 varied from 0.69 to 0.92 and the RMSE from 0.003 to 0.008. Additional simulations with HYDRUS were used to evaluate the effects of various design parameters on the desalination zone. The relationship between irrigation volume and the size of the desalination zone was found to follow a power function (R2 = 0.951), and that between emitter discharge and the size of the desalination zone was found to follow an exponential function (R2 = 0.9995). A negative relationship was found between emitter spacing and the size of the desalination zone. For loam, the vertical extent of desalination was found to be about 1.3 times that of the horizontal. For loamy sand, the vertical extent of desalination far exceeded the horizontal extent, owing to its large hydraulic conductivity. We hope that these simulation results with HYDRUS-3D can provide a basis for designing suitable drip irrigation systems. Pages 238-247 | Full Text PDF |
Hydrogen sulfide protects wheat seedlings against copper stress by regulating the ascorbate and glutathione metabolism in leaves Changjuan Shan, Huiping Dai, Yanfang Sun Abstract This study investigated the effects of exogenous hydrogen sulfide on the ascorbate and glutathione metabolism in wheat seedlings leaves under copper stress. The results showed that copper stress induced the increases in the activities of APX, DHAR, MDHAR, GR, GalLDH and ?-ECS, and the contents of AsA, GSH, total ascorbate and total glutathione. Pretreatment with sodium hydrosulfide (NaHS), a hydrogen sulfide (H2S) donor, enhanced the activities of GR, DHAR, GalLDH and ?-ECS, and the contents of AsA, GSH, total ascorbate and total glutathione under copper stress. Meanwhile, pretreatment with NaHS decreased the malondialdehyde content and electrolyte leakage induced by copper stress in plants. Our results suggested that exogenous hydrogen sulfide alleviated oxidative damage by regulating the ascorbate and glutathione metabolism under copper stress, and H2S has important role for acquisition of copper stress tolerance in wheat seedlings. Therefore, exogenous hydrogen sulfide can be used as a regulator to improve crop tolerance under copper stress. Pages 248-254 | Full Text PDF |
Evaluation of inhibitory effects of extracts of plants from western Iran against Phytophthora drechsleri S.Bahraminejad, S.Abbasi, S.M.Maassoumi and S. Tabein Abstract Crude aqueous and methanol extracts of 121 plant species from 41 families, collected from the west of Iran, were screened for antifungal activity against mycelial growth of Phytophthora drechsleri. The bioassay used was based on the paper disc diffusion method with four replicates. Extracts of 38 of 121 (about 31%) plant species had inhibitory activity against this phytopathogenic fungus, among which 23 species measurably inhibited the growth of Phytophthora drechsleri. A methanol extract of Xanthium strumarium had the strongest inhibitory activity (17.79±1.35 mm) against P. drechsleri followed by extracts of Glycyrrhiza glabra, Verbascum sp., Hypericum perforatum, Centaura depressa, Centaura sp., Lamium amplexicaule, Haplophyllum perforatum. An investigation of the efficacy of extracts of different plant parts on mycelial inhibition of P. drechsleri, using the paper disc method, indicated that the inflorescence and fruits of cocklebur (Xanthium strumarium) showed significantly more inhibitory effect than the other plant parts against the fungus. Two common species of cocklebur, X. strumarium and X. spinosa, grown around the city of Kermanshah, inhibited mycelial growth of the tested fungus, but extracts of X. strumarium had significantly more inhibitory effect against P. dreschleri than X. spinosa. The results of fractionation of leaf, fruit and inflorescence by thin layer chromatography (TLC) indicated that yellow and blue fractions (under UV) with relative fronts (Rf) equal to 0.93 and 0.98 of leaf, fruit and inflorescence fractions exhibited the highest inhibitory effect against P. dreschleri. These results suggest that cocklebur has potential for control of P. dreschleri and further green house and farm studies are recommended. Pages 255-260 | Full Text PDF | Supplementary data |
Morphological and molecular analyses define the genetic diversity of Asian bitter gourd (Momordica charantia L.) Dalamu, T.K Behera, A.B Gaikwad, Swati Saxena, C Bharadwaj, A.D Munshi Abstract Bitter gourd (Momordica charantia L.) is a nutritious vegetable crop of Asian origin. Fifty indigenous and exotic bitter gourd genotypes were characterized using 12 quantitatively inherited traits and genotypic variation analysed using RAPD and ISSR markers. Based on the morphological traits, the first female flower appeared at lowest node (9th node) in gynoecious genotypes DBGy201 and DBGy202. Sel-2 possessed the highest yield per hectare (10,866 kg). Seventeen RAPD markers produced 84 amplicons in 50 accessions, of which 33 (41.34 %) were found polymorphic. Joint comparisons among the 50 accessions using Jaccard’s similarity coefficient indicated that genetic distances (GD) ranged from 0.03 to 0.28. Eleven ISSR primers provided a total of 58 amplicons of which 41 (70.0 %) were polymorphic in 50 accessions. The Jaccard’s similarity coefficient matrix values ranged from 0.50 to 0.95 based on molecular analysis. The polymorphic information content (PIC), resolving power (RP) and marker index (MI) were 0.17, 1.14 and 0.82, respectively for RAPD markers, whereas ISSR markers showed comparatively high polymorphic information content (0.40), resolving power (1.87), and marker index (2.11). The combined data analysis of RAPD and ISSR markers indicated that the relative polymorphism among accessions was 52.6 % with 2.64 polymorphic amplicons per primer. The value of average polymorphic information content, resolving power and marker index were 0.26, 1.42, and 1.33, respectively. These data demonstrate a large genetic variability among the Asian bitter gourd genotypes examined, which indicates that they should be considered as a valuable gene pool for bitter gourd breeding programs. Pages 261-267 | Full Text PDF | Supplementary data |
Genetic variation among Iranian pomegranates (Punica granatum L.) using RAPD, ISSR and SSR markers Zahra Noormohammadi, Ali Fasihee, Saeed Homaee-Rashidpoor, Masoud Sheidai, Somayeh Ghasemzadeh Baraki, Ali Mazooji, Seyed Ziaedin Tabatabaee-Ardakani Abstract Pomegranate (Punica granatum L.) is one of important horticultural plants in Iran with about 800 genotypes cultivated in several regions of country. Three molecular markers including RAPD, ISSR and SSR were used to evaluate genetic diversity of thirty six Iranian pomegranate genotypes. Genetic parameters consisted of effective alleles (Ne), Nei genetic diversity (H), Shannon index (I) and polymorphic information content (PIC) were calculated based on molecular data. SSR markers with their co-dominant nature showed the highest value of genetic parameters aforementioned except PIC value among all markers. Combined data of three markers showed higher genetic diversity than two ISSR and RAPD markers. UPGMA tree obtained from combined molecular data (total 235 amplicons) discriminated pomegranate genotypes in three major groups. Principle Component Analysis (PCA) based on the first two components confirmed clustering. The homonymous, synonymous and/or mislabeled genotypes were identified using three molecular markers. The analysis of molecular variance (AMOVA) indicated no significant genetic variation (p= 0.27) between pomegranate genotypes in different localities (seven locality groups). Only 2% of overall genetic variation was due to among locality groups differences while 98% of variation was due to within group differences. Pages 268-275 | Full Text PDF |
Association of SSR markers with partial resistance to Sclerotinia sclerotiorum isolates in sunflower (Helianthus annuus L.) R. Darvishzadeh Abstract Basal stem rot, caused by Sclerotinia sclerotiorum (Lib.) de Bary, is one of the most important diseases of sunflower in the world. The objective of present study was to estimate the number of markers and genomic region associated with basal stem rot resistance in sunflower. The genetic variability among 15 sunflower genotypes from different countries of origin was evaluated using 38 simple sequence repeat (SSR) markers. 88 markers were generated at 38 SSR loci and the mean for the number of allele per locus was 2.32. The UPGMA clustering algorithm based on Jaccard’s coefficient of similarity classified the studied genotypes into three distinct groups. Marker-trait associations were studied for disease susceptibility of 15 sunflower genotypes against seven S. sclerotiorum isolates through one way ANOVA using a set of 88 SSR markers. Using ANOVA method fifteen putative SSR markers were detected for partial resistance against isolates. Two out of 15 SSR markers was common between some isolates whereas the others were specific for each isolate. ORS 1265 was common for SSU35 and SSU87isolates, and ORS 149 was common for SSU53 and SSU55 isolates. Regarding isolate-specific and isolate-nonspecific markers detected for partial resistance, it is evident that both genetic effects control partial resistance to S. sclerotiorum isolates. This confirms the need to consider different isolates in the basal stem rot resistance breeding programs. Pages 276-282 | Full Text PDF |
Some physiological and enzymatic characterizations of Damask Rose accessions (Rosa damascena Mill.) Bahareh Kashefi, Seyed Reza Tabaei-Aghdaei, Mohammad Matinizadeh, Amir Mousavi, Aliashraf Jafari Abstract Climate can be a potent selective agent on life history and physiology of plants. Rosa damascena Mill. is an important aromatic, ornamental and medicinal species with a high genetic variation in Iran. In order to investigate the phenological stages, 12 damask rose accessions were collected from Damavand region. Some physiological (proline, chlorophyll, leaf area, stomata density and dry weight percentage) and enzymatic characteristics were analyzed in 3 phenological stages during two years (2008-2009). Results revealed significant differences and interactions among accessions, years and seasons. Thus, this study showed the highest proline content and peroxidase activity in the second year but other traits indicated maximum level in the first year. Furthermore, third phenological stage was the strongest for some traits except proline and leaf area content. The results of this research allow the documenting of responses of Damask Rose accessions to environmental conditions and genotypic differences by some physiological and enzymatic activities. Consequently, this research could introduce Tehran as hardening and Fars as sensitive accessions. Pages 283-290 | Full Text PDF |
Assessment of clonal fidelity of micro-propagated guava (Psidium guajava) plants by ISSR markers Xiaomei Liu, Guochen Yang Abstract Inter-simple sequence repeat (ISSR) was used to assess the genetic stability of micro-propagated plantlets of guava. Thirty one plantlets were chosen from a clonal collection of shoots that originally from a single mother plant. Out of 21 ISSR primers screened, 16 primers were found to produce clear, reproducible bands resulting in a total of 93 distinct bands with an average of 6.5 bands per primer. Of these 93 bands, 84 were monomorphic across all 31 of the plants tested and 9 showed polymorphisms (9.67% polymorphisms). Based on the ISSR band data, similarity indicators between the progenies and the mother ranged from 0.92 to 1.0, such a similarity indicated a very low polymorphism. These similarities indices were used to construct an UPGMA dendrogram and demonstrated that all 31 micro-propagated plants grouped together in one major cluster with a similarity level of 92%. A total of 2356 scorable bands were obtained from the full combination of primers and plantlets and only 39 (1.65%) were polymorphic across the plantlets which indicated that the micro-propagated guava is genetically stable. Pages 291-295 | Full Text PDF |
Molecular cloning, expression analysis and growth temperature dependent regulation of a novel oleate desaturase gene (fad2) homologue from Brassica juncea Suresha G.S, Rai R.D, Santha I.M Abstract In plants the endoplasmic reticulum (ER) associated oleate desaturase (FAD2) is the key enzyme responsible for the production of linoleic acid in non- photosynthetic tissues. In the present study, we isolated a novel gene encoding fad2 isoform through RT-PCR, designated as Bjfad2 (Gen Bank Accession No. EF639848) from Brassica juncea, important source of edible oil in India. The cDNA sequence of Bjfad2 was 1,445 bp containing a 1,155 bp open reading frame (ORF) encoding a polypeptide of 384 amino acids. The deduced amino acid sequences of the isolated gene displayed the typical three histidine boxes, characteristic of all membrane bound desaturases and possessed a C-terminal signal for ER retention. Phylogenetic analysis showed Bjfad2 grouped within the plant housekeeping-type fad2 genes. Genomic Southern blot analysis was consistent with the presence of atleast two copies of Bjfad2 gene in B. juncea genome. Study of tissue specific expression confirmed that Bjfad2 was constitutively expressed in both vegetative tissues and developing seeds. Expression of Bjfad2 gene is developmentally regulated with increased expression in mid-maturation stage [30 days after flowering (DAF)], as compared to early (15 DAF) and late (45 DAF) stages of seed development. Real time PCR analysis of fad2 expression showed one-fold higher under the lower temperature and three fold lower under the higher temperature treatments. Differences in fatty acid contents among the temperature treatments were consistent with the expression data of the gene. Differential expression of the fad2 gene was observed between high and low erucic acid B. juncea genotypes. Pages 296-308 | Full Text PDF |
Comparison of adaptive strategies of alfalfa (Medicago sativa L.) to salt and alkali stresses Xiaoping Wang, Wanchao Chen, Ying Zhou, Jiayu Han, Jing Zhao, Decheng Shi, Chunwu Yang Abstract Alfalfa seedlings were stressed with salt or alkali. The growth, organic acids (OAs) and inorganic ions in stressed seedlings were measured to investigate the physiological adaptive mechanism, by which alfalfa tolerates alkali stress. For this purpose, we conducted some experiments under different salt and alkali stresses and then compared the results. The results showed that salt stress significantly stimulated alfalfa root growth. However, alkali stress decreased root dry weight by 20.83% compared with control treatment at 7 days (d). In root of seedlings subjected to alkali stress for 3 d, accumulation of Na+, citrate and malate was strongly stimulated and raised by 763.29%, 217.47% and 298.00%, respectively, compared to control. However, in shoots, only when seedlings were subjected to alkali stress for 7d, the accumulation of contents increased sharply, indicating that response of root to alkali stress is more sensitive than that of shoot. Alkali stress greatly enhanced the Na+ content, reduced the contents of inorganic anions, and induced deficit of negative charges. Under salt stress, Cl? content heavily increased, and the contribution of OAs to osmotic adjustment was less than that of inorganic ions. Under alkali stress, alfalfa enhanced the synthesis of organic acids (OAs) (mainly citrate and malate) to compensate the shortage of inorganic anions. The OA metabolic regulation might play an important role in maintaining ion balance. Pages 309-315 | Full Text PDF |
Differential proteomic expressions between superior and inferior spikelets of rice in response to varied nitrogen treatments Zhixing Zhang, Jun Chen, Zhong Li, Hongfei Chen, Changxun Fang, Jinwen Huang, Wenxiong Lin Abstract Grain-filling and molecular mechanisms of Indica rice jinhui No.809 (large-panicle type) were investigated. By keeping the total N supply constant and varying the early and late growth stage fertilizer application ratios, changes in the protein expressions of the rice superior and inferior spikelets were determined. The two N fertilization treatments were traditional and modern nitrogen applications (TNA and MNA). Using 2-DE and MALDI-TOF/MS, 38 proteins were identified to show differential expressions in response to the different N treatments. MNA appeared to promote protein up-regulation in the inferior spikelets, including cell respiration related proteins (e.g., fructose-bisphosphate aldolase, phosphoglycerate mutase, glyceraldehyde-3-phosphate dehydrogenase, malic oxidoreductase, succinate dehydrogenase, transketolase, phosphoglucomutase, and some starch synthesis related proteins (e.g., phosphoglucomutase, WRKY, glycolipid transfer and fatty acid hydroxylase) clearly indicating that the increased N supply at the late growth stage was favorable for the grain-filling of inferior spikelets. Moreover, the up-regulated auxin-responsive protein IAA22 and gibberellin response modulator implied that the MNA treatment could increase the content of phytohormones in inferior spikelets. In addition, the proteomic analysis and physiological observations in the present study also elucidated the mechanism underlying the asynchronous grain-fillings between the superior and inferior spikelets of rice. Pages 316-325 | Full Text PDF | Supplementary data |
Comparison of phenotypic and molecular characterizations of some important wheat cultivars and advanced breeding lines Abdollah Najaphy, Reza Ashrafi Parchin, Ezatollah Farshadfar Abstract Analysis of genetic variation is fundamental to plant breeding programs. The present study evaluated genetic diversity of thirty wheat cultivars and advanced breeding lines using phenological and agro-morphological characters and molecular markers (ISSRs) data. The field experiment was carried out in growing season of 2008-2009. The measured phenotypic traits (20 traits) illustrated significant differences among the wheat accessions. Variation for most of the traits was observed. The clustering pattern based on phenotypic data using WARD method assigned the wheat genotypes into four groups. The ten ISSR primers amplified a total of 86 bands in the set of thirty wheat accessions, of which 69 bands (80.2%) were polymorphic. The majority of the primers showed polymorphism information content (PIC) values close to the average (0.21-0.23), indicating diverse nature of the wheat accessions and/or highly informative ISSR markers used in this study. The genotyping data of the ISSR markers were used to assess genetic variation in the wheat accessions by CLINK- based dendrogram and principle coordinate analysis (PCoA). Both of the methods classified the 30 wheat accessions in five groups and presented similar grouping of the genotypes with some minor deviations. The results showed that the studied ISSR markers, provided sufficient polymorphism and reproducible fingerprinting profiles for evaluating genetic diversity of wheat genotypes. The analyzed wheat accessions showed a good level of genetic variability for both assessed quantitative and molecular characters. No correlation was found between variation measurements identified using molecular markers and quantitative traits. Molecular variation evaluated in this study in combination with agronomic and morphological characters of wheat can be useful in traditional and molecular breeding programs. Pages 326-332 | Full Text PDF | Supplementary data |
Review article Technology and field management for controlling soil salinity effects on cotton Hezhong Dong Abstract Soil salinity is a major threat to cotton production worldwide. Excessive salt in the soil leads to a series of physiological and biochemical metabolic disorders in cotton plants mainly as a result of osmotic effects (dehydration), nutritional imbalance and toxicity of salt ions (Na+ and Cl-). The metabolic disorders may finally reduce plant growth and lint yield and quality, particularly in conditions of high salinity. Basically, combating the effects of salinity stress on cotton plants involves two main strategies: one is to improve salt tolerance through genetic breeding and chemical or biological treatment, the other is to avoid or alleviate salinity stress by improving at least part of the root-zone environment. This review highlights the technologies for combating salinity stress on cotton, with a focus on recent advances in agronomic techniques for managing salinity in the root zone. We recommend a comprehensive use of agronomic practices such as suitable cultivars, proper irrigation and fertilization, seed pretreatment, furrow seeding, plastic mulching and induction of unequal salt distribution in the root-zone to combat salinity stress. Further research should focus on exploration and understanding of the uptake and efficient use of water and nutrients in saline soils. Research should also focus on the development of new products for cotton growing in saline soils like new foliar and specific slow-release fertilizers and commercial plant growth regulators to improve salt tolerance. Pages 333-341 | Full Text PDF |
Genetic diversity in the foxtail millet (Setaria italica) germplasm as determined by agronomic traits and microsatellite markers Heng-Sheng Lin, Gwo-Ing Liao, Chih-Yun Chiang, Chang-Sheng Kuoh, Song-Bin Chang Abstract Setaria italica (L.) P. Beauv. is a model plant that attracts international attention, which is the second most widely cultivated species of millet, especially in East Asia. It has the longest history of cultivation among the millets, having been grown in China since sometime in the sixth millennium BC. It also has been a main crop of the indigenous people of Taiwan for a long time. However, insufficient researches had been conducted about the foxtail millet germplasm in Taiwan. To assess the genetic diversity of millet population, a total of 324 landraces of foxtail millet were collected from around Taiwan, and four years of field researches were conducted for agronomic traits observation. The genetic diversity of the millet population was measured using 33 agronomic traits and 40 microsatellite markers. Average number of alleles (2.4), highly polymorphic information content (PIC) (0.381), observed heterozygosity (0.190) and expected heterozygosity (0.354) were shown. Thirty-five SSR markers showed significant deviation from Hardy-Weinberg equilibrium in 324 landraces and all these markers had low null allele frequencies. Analysis with the Unweighted Pair Group Method with Arithmetic Mean (UPGMA) method and Principal Component Analysis (PCA) revealed that the 324 landraces could be divided into three groups that coincided with the geographical areas, including northern Taiwan, central Taiwan, and sourthern Taiwan, which account for close relationship between crop distribution and human activities. Agronomical analyses with a plant height of 80.6 to 155.2 cm, spike length of 7.5 to 28.9 cm and growth periods of between 141 and 178 days had showed that there was enough variation to create promising lines for breeding programs. This study not only provides a complete foxtail millet germplasm from Taiwan but also demonstrates that the Taiwanese foxtail millets are very diverse and can be useful for selective breeding of specific traits and in enhancing the genetic base of breeding programs in the future. Pages 342-349 | Full Text PDF | Supplementary data |
Management of leaf spot disease of Stevia rebaudiana Bertoni with antagonistic bacteria Surjit Sen, Gunjan Biswas, Saikat Kumar Basu, Krishnendu Acharya Abstract Stevia rebaudiana Bertoni, a natural sweetener contains two main sweetest compounds, stevioside (ST) and rebaudioside A (R-A), tasting about 300 and 450 times sweeter than sucrose, respectively. This commercially important plant also suffers a leaf spot disease caused by the fungus Alternaria alternata in various districts of South Bengal, India. Fluorescent Pseudomonas BRL-1 isolated from the rhizosphere, showed both in vitro and in vivo antagonistic activity against the pathogen. In dual culture bioassay as circular and semicircular patterns, the isolate quantitatively inhibits the growth of the pathogen by about 78% and 69%, respectively. In vitro plate assay detected that the strain produces hydrolytic enzymes, IAA and siderophore. In talc based formulation the strain has adequate shelf life. Experimental data illustrates about 70% survivability of the population after 180 days of storage at 4°C. Foliar application of the talc based formulation of the antagonist in the field condition revealed that the maximum mean disease index reached to 0.653 and 0.663 in 2009 and 2010, which showed around 86% and 87 % reduction in disease severity, respectively when compared to control. Transferring the outcome of this work in the field would benefit the growers by facilitating bioorganic production of this important medicinal plant. Ultimately, the consumers will tend to receive a pesticide free natural sweetener. Pages 350-356 | Full Text PDF |
Effect of NaCl salinity on water relations, photosynthesis and chemical composition of Quinoa (Chenopodium quinoa Willd.) as a potential cash crop halophyte S. Eisa, S. Hussin, N. Geissler, H.W. Koyro Abstract Despite the large interest in the use of Chenopodium quinoa as a crop on extreme habitats, very little is known about growth response and seed yield under saline conditions. As a prerequisite for its sustainable utilization in salt-affected areas, this study aimed to unravel individual physiological and morphological mechanisms that determine its salt tolerance. Hence, the plants were grown in a hydroponic quick check system with 0, 100, 200, 300, 400, and 500 mM NaCl (equivalent to 0, 20, 40, 60, 80 and 100% seawater salinity). Growth of C. quinoa was slightly stimulated with increasing water salinity, with an optimum at 100 mM NaCl. This was mainly due to enhanced tissue water content and succulence. Higher salinities considerably reduced plant growth, with maximum reduction of 82% observed at 500 mM NaCl. The plants were able to reduce the leaf water potential below the soil water potential. This was associated with substantial decrease in osmotic potential mainly by accumulation of Na+ and Cl-. Interestingly, the plants were able to maintain favorable ion relations in their roots and juvenile leaves, where the metabolic demands are expected to be greatest even under high NaCl salinity. The net photosynthesis rates were greatly decreased by high salinity, being 28% of initial control values at 500 mM NaCl. Salt-induced photosynthesis inhibition was accompanied with a decrease in transpiration rates but also with improved water use efficiency. Neither osmotic stress nor ion deficiency/toxicity appeared to be determinant for C. quinoa under high saline condition. Salt-induced growth reduction is presumably due to low photosynthate supply as a consequence of impaired photosynthetic capacity. Together, these indicate that C. quinoa is a promising salt-tolerant, in terms of biomass production and can be grown productively under low to moderate saline condition up to 40% sws. Pages 357-368 | Full Text PDF |
Evaluation of Jelutong (Dyera cotulata) as a phytoremediator to uptake copper (Cu) from contaminated soils Nik M. Majid, M.M. Islam, Redzuan Abdul Rauf Abstract Soil pollutants including are being mixed with agricultural soils and water. The potential accumulation of heavy metals in human and animal body is dangerous and causes several detrimental effects and diseases. An experiment was conducted in the glasshouse to evaluate the potential of Dyera costulata as a phytoremediator to absorb copper (Cu) from contaminated soils. Dyera costulata seedlings were planted in the growth media (soil + different levels of copper). The different levels of Cu were: T0 (control, soil), T1 (50 ppm Cu), T2 (100 ppm Cu), T3 (200 ppm Cu), T4 (300 ppm Cu) and T5 (400 ppm Cu). The highest growth performance such as basal diameter, height and number of leaves and the highest biomass were found in T2. The highest accumulation of Cu (89.97 ppm) was recorded in T5. Among the plant parts, roots showed the highest concentration of copper. Dyera costulata showed a high translocation factor (TF) value in soil at low to medium Cu concentrations as it was able to tolerate and accumulate high concentrations of Cu. The roots of Dyera costulata were the main part of plant that absorbed copper in contaminated soils. This species can be an efficient phytoremediator for soils contaminated with copper. Pages 369-374 | Full Text PDF |
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