International Journal of Plant Production
Volume:4 Issue: 2, Apr 2010

Mulberry (Morus alba L.) belongs to family Moraceae، is a multipurpose woody perennial، deciduous tree and is mainly cultivated for sericulture. Salt problem is considered as one of the most important environmental factors، limiting plant growth and productivity of arid and semiarid regions. During stress conditions plants need to maintain internal water potential below that of soil and maintain turgor and water uptake for growth. This requires an increase in osmotica، either by uptake of soil solutes or by synthesis of metabolic (compitable) solutes. One of the most common stress responses in plants is overproduction of different types of compitable organic solutes e. g. proline، protein، sugar etc. (Ahmad et al. ، 2006; Ahmad et al. ، 2008; Ahmad and Sharma، 2008). The accumulation of proline is thought to function as osmoprotectant and is a unique plant response to environmental stress. Soluble proteins and sugars have also been shown to accumulate under salt stress (Ahmad and Jhon، 2005). Several biochemical processes are affected by salinity، particularly nitrate assimilation and nitrate reductases activity (NRA) (Ahmad and John، 2005). The present study was performed to evaluate the effects of salt stress on growth، water relations and gas exchange of two mulberry cultivars.

Basil (Ocimum basilicum) is one of the important medicinal plant species. In order to produce an autotetraploid population of basil (Ocimum basilicum) by colchicine، different concentrations (0. 00، 0. 05، 0. 10، 0. 20، 0. 50 and 0. 75%) and four treatment methods were examined (seed، the growing point of seedlings at the emergence of cotyledone leaves stage and emergence of true two type leaves stage، and root treatment) to determine the best treatment for the induction of tetraploid plants. Autotetraploid plants were produced only by treatment of growing point of seedlings، at the emergence of cotyledone leaves stage، and treatment with 0. 5% proved to be the most effective in producing autotetraploids. The induced tetraploids in basil was accompanied by larger stomata and pollen grains، increase in chloroplast number in guard cells and decrease in stomata density، compared to diploid control plants. In order to distinguish the induced colchicine tetraploid plants from the diploids، morphological changes and techniques as stomata size، number of chloroplasts per guard cell، pollen grain diameter and flow cytometry were considered and proved that these methods are suitable، quick and easy methods for identification the ploidy level of Ocimum basilicum in various stages of the plant development of these species and among this methods flow cytometry as found to be the most efficient method for detecting induced changes in ploidy level. Keywords: Colchicine; Cytological traits; Flow cytometry; Ocimum basilicum; Tetraploidy induction.

In a three-year (2004-2006)، field experiment، we aimed to study changes in leaf physiological traits (leaf water potential-Ψleaf، leaf water content-LWC، carbon isotope discrimination-Δ، specific leaf area-SLA، chlorophyll content as assessed by SPAD and modified SPAD-MSPAD) and elemental composition (K، Na، Ca، Mg، K/Na، Ca/Mg، total leaf salinity-TLS) of sugar beets (cv. Rizor) grown under Mediterranean، irrigated conditions. Each year، soil moisture content (SMC) and leaf parameters were determined 11 times from early June to the end of October. Growing seasons differed as regards water inputs with 2004 being the driest and 2006 being the wettest. Leaf physiology and chemistry showed plasticity to water availability and significant differences were found between years (except for Ca)، sampling time and their interaction. Ψleaf، LWC، Δ، SLA، K/Na and Ca/Mg were positively affected by SMC while the adverse was evident for chlorophyll content (SPAD and MSPAD)، Na، Ca، Mg and TLS. As a Chenopodiaceae، sugar beet used leaf succulence، lowering SLA، to cope with water shortage and maintain LWC ca 90%. Low SLA was related with low Ψleaf and Δ values. Succulent leaves were characterized by increased leaf salinity and chlorophyll accumulation، which was ascribed to increased Mg concentrations. Leaf salinity and mainly Na had a negative impact on Δ. Antagonistic effects of K on Na or Mg and synergistic effects of Na on Ca and Mg were recorded. Keywords: Beta vulgaris L; Carbon isotope discrimination; Drought; Photosynthesis; Specific leaf area; Water use efficiency

The results of studies on in vitro regeneration of chickpea (Cicer arietinum L.) have shown that indirect regeneration via callus was not successful. The introduction of an efficient and repeatable regeneration protocol is necessary for using transgenic technologies for the improvement of chickpea. The present study was undertaken to investigate the possibility of indirect regeneration in various chickpea genotypes. In this experiment، cotyledonary node explants of 20 chickpea genotypes were cultured on 6 callus induction media and were sub-cultured on 6 shoot induction media with different combinations of phytohormons that are introduced in other literatures as best combination for regeneration. The results showed that reduction in experimental time and cost was possible by only transferring green calluses to other processes of culture. It seems that the results of this study and the suggested protocol could be used in genotypes as MCC426، MCC495، MCC496، MCC724، MCC741، MCC763، MCC764، MCC769، MCC775، MCC 779، MCC780، MCC798، MCC805 and MCC814 in suggestive media for genetic transformation and other projects where organogenesis via callus formation is necessary. Keywords: Chickpea (Cicer arietinum L.); Callus-mediated shoot formation; Zeatin; IBA; Organogenesis; Regeneration

Screening of twenty-four candidate plus trees from naturally available Pongamia pinnata genetic resources was carried out to elucidate the genetic variation and relationship of pod and seed traits on germination capacity to select the best planting material for higher productivity. The experiment conducted at Forest Research Centre، Institute of Forest Productivity Mandar، Ranchi during 2005-2006. Variability studies reveled that، genotype CPT-19 recorded maximum values for six traits viz. pod length (65.64 mm)، 100-pod weight (542.35 g)، 2D surface area (351.18 mm2)، seed length (27.93 mm)، 100-seed weight (202.89 g) and total oil content (44.33%). However، maximum pod thickness (12.72 mm)، seed length (17.49 mm)، pod-seed ratio (2.89) germination capacity (94.67%) was recorded by the genotype CPT-6. The phenotypic and genotypic coefficients of variations were also close to each other for all traits، but 100-pod weight and 100-seed weight exhibited higher phenotypic coefficients of variation and genotypic coefficients of variation than the other traits. Estimates of broad sense heritability ranged from 0.82 (for seed length) to 0.98 (for 100-pod weight)، genetic advance as percent of the mean ranged between 12.30% and 46.04% with seed length giving the lowest value and 100-pod weight giving the highest value. Germination capacity exhibited positive significant correlation with pod width، 100-pod weight، 2D surface area and seed width at both genotypic and phenotypic level. However، pod length، pod thickness and 100-seed weight expressed positive significant correlation only at genotypic level. Path analysis of pod and seed traits revealed that، the 100-pod weight (0.909) is the most pronounced character contributing directly to germination capacity followed by seed length (0.785) and pod length (0.324). In conclusion، the results revealed the existence of substantial genetic variation، which can be utilized for genetic resources conservation in gene bank and further tree improvement programmers of the species. Keywords: Correlation; Genetic advance; Heritability; Image analyzer; Pongamia pinnata; Path co-efficient; Variability

Hybrids as various resources have valuable importance in tree breeding. Today، improvement programs by using poplar and willows and their hybrids play basic role in supplying wood and decreasing pressure on natural forests. This research was carried out in order to study inter-generic hybridization possibility between Salix aegyptica and Populus caspica species from Salicaceae to achieve new hybrids. Embryo rescue technique was used in order to produce new inter-generic hybrids in salicaceae. The experiment was performed in factorial completely randomized design with 3 replication in embryo developmental stages and different media treatments. The analysis of data showed that inter-generic cross ability between Salix aegyptica and Populus caspica was possible and 14 day after pollination and MS medium containing 3 percent sucrose were the best time and medium for obtaining high amount of germinated hybrids. Keywords: Inter-generic hybridization; Populus caspica; Salix aegyptica; Tree breeding.

Duration of various stages of inflorescence differentiation and hormone levels in apical buds eventually decide the harvest time، flower uniformity and quality of ornamental plants. The progress in inflorescence differentiation process in the chrysanthemum cultivar ‘Jingyun’ can be divided into nine stages. Following short day induction، it took 4d to reach the growing point hypertrophy stage، 8d to finish involucre primordia differentiation، 12d to finish floret primordia differentiation and 10d to finish crown formation. Under inducible conditions، the level of indole acetic acid (IAA) initially decreased، but maintained a relatively high level during the whole period of inflorescence differentiation. Both N6- (Δ 2-isopentenyl) -adenosine (iPA) and abscisic acid (ABA) levels increased markedly during floral induction and floral initiation، peaking at the final involucre primordia differentiation stage. Thereafter، the iPA level remained high، while the ABA level decreased. A large decrease in the level of gibberellic acid (GA3) occurred during floral induction، but this recovered by the final floret primordia differentiation stage. In conclusion، various stages of inflorescence differentiation take different time-span، the floret primordia differentiation takes the longest time-span، while time-span for involucre primordia differentiation is shortest. Moreover، an appropriate amount of IAA appears to be necessary for inflorescence differentiation، and a stable GA3 and ABA level for crown formation. iPA plays a positive role both in floral induction and inflorescence differentiation. Keywords: Chrysanthemum; Floral induction; Inflorescence differentiation; Plant hormones