Journal of Plant Physiology and Breeding
Volume:3 Issue: 1, Winter-Spring 2013

This study was conducted on two canola (Brassica napus) cultivars, Okapi a winter type and cold tolerant and Rgs003 a spring type and cold sensitive. Seedlings were grown in an environmentally controlled growth room with 16 h d-1 photoperiod at 22/16 °C (day/night, control). At the 4-leaf stage, half of pots were transferred to a cold growth room for 7 d at 10/3°C (day/night, cold treatment) and their leaves were harvested as required on 0, 2, 4 and 7 d as four sampling times. Superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) activity and the amount of malondialdehyde (MDA) in samples were assessed. Analysis of variance showed that winter canola had more SOD, CAT and APX activity, lower amount of either MDA or POD activities compared with the spring canola. This study indicated that antioxidant mechanisms caused more cold tolerance in the winter cultivar of canola compared with the spring cultivar.

Peppermint (Mentha piperita L.), a herbaceous and perennial species whichis produced mainly for the medicine and food. The peppermint plants were initiated from 10 cm-long rhizome cuttings followed by transferring into pots. The 48 h-treated plants with methyl jasmonate (MJ) concentrations (0, 0.1, 0.5 mM) were assessed for their total soluble proteins, malondialdehyde (MDA), chlorophylls a, b and total, anthocyanin, total carbohydrates, carotenoid, activity of antioxidant guaiacol peroxidase (POD) and superoxide dismutase (SOD) enzymes. The data were analyzed using completely randomized design (CRD) with three replications. Mean comparisons were carried out, using Duncan''s multiple range test. MJ treatment caused significant changes in soluble proteins, chlorophylls (a, b and total), MDA, carbohydrates and antioxidant enzymes (SOD and POD) but had no effect on antocyanin and carotenoid. These results indicate that MJ can effectively improve the defense system and antioxidant capacity of peppermint.

The effects of lead on the proline content and dry weight of leaves and roots were investigated in two canola cultivars (Brassica napus L.) grown in the Hoagland solution. The growth of treated plants was inhibited under lead stress. Lead induced differential accumulation of proline in canola grown in solution with the addition of 0, 100 and 200 mgL-1 of Pb. Hyola308 cultivar showed low biomass reduction under stress condition (lead-tolerant genotype). The younger leaf (second leaf) showed low reduction in dry weight under stress and root growth decreased progressively with increasing concentration of Pb. This reduction was remarkable in the Sarigol cultivar. There was a low Pb accumulation in the lead-tolerant genotype (Hyola 308). Canola had the ability to accumulate Pb primarily in its roots (especially in the case of Hyola308 0) and accumulated it in the shoots in much lesser concentrations. For the younger leaf increment in proline content was about two-fold. Proline content in roots was found to be lower than that of leaves under non-stress condition. Although there was linear dose dependent increase in the proline accumulation in roots, yet their magnitude was lower than the related values for leaves. However, this trend was reversed under high stress level. Under this condition, proline accumulation was consistently higher in the younger leaf. Furthermore, proline content in the roots of lead-susceptible cultivar was higher than the second and third leaf.

The use of nitrogen in nutrient media is essential for growth and helps identify highly productive media for potato (Solanum tuberosum L.) micropropagation and adventitious shoot formation. Three potato cultivars (Agria, Marfona and Savalan cultivars) were examined for their growth response with medium containing four different levels of KNO3 (1, 1.25, 1.5 and 1.75 times as much 1.9 g l-1) and NH4NO3 (1, 1.25, 1.5 and 1.75 times as much 1.65 g l-1). The morphogenic responses of cultivars were evaluated via measurement of root length, number of roots, shoot length, number of shoots and number of nodes per plantlet. Results indicated that the cultivars differed in their response to nitrogen source types and different concentrations. The results of both KNO3 and NH4NO3 experiments indicated that N3C1 and N3C2 (2.85 g l-1 KNO3 and 2.475 g l-1 NH4NO3in Agria and Marfona, respectively) had the longest shoot length. Cultivars Agria and Marfona at 2.375, 2.85 and 3.325 g l-1 KNO3 produced the shortest root length, but cultivar Savalan in all KNO3 levels had the highest root length. Our findings indicated that the third concentration of both nitrogen sources (KNO3 and NH4NO3) were better than other nitrogen concentrations in all cultivars for number of shoots and number of nodes. Therefore, nitrogen source media should have significant utility for shoot or other important traits in potato in vitro culture conditions.

Wheat is a crop with spring and winter types and wide adaptability to different climate conditions. The wide adaptability of wheat is mainly controlled by three groups of genetic factors and among them vernalization (VRN) genes play pivotal role in determining spring and winter types. In this study, 395 Iranian wheat landraces were characterized with specific primer pairs designed based on VRN-1 promoter and intron regions. Using the specific primers for Vrn-A1c allele, two fragments were amplified in 35 genotypes. Based on MADS-Box and promoter regions of VRN-1 gene specific primers, two new fragments were amplified in Iranian wheat landraces which has not been reported previously. Vrn-A1b allele determining spring habit was the most frequent allele, whereas Vrn-A1c showed less frequency. Frequency of dominant allele Vrn-A1b, in winter genotypes was higher than that of spring type. It supports the presence of other regulatory sites outside of the VRN promoter region.

In the current study, a set of 96 recombinant inbred lines (RIL) at F8, derived from a cross between two varieties, Anbarbu (sensitive to drought stress) and Sepidroud (tolerant to drought stress) were used. The experiment was performed at Gonbad Kavous located in the Golestan province of Iran in 2010–2011 using two augmented designs at normal and stress conditions, separately. The RIL population was assessed for 11 agronomic traits including grain yield, panicle number, panicle length, grain number, grain weight, straw weight and secondary branches number. Linkage map with 135 microsatellite markers was used to map quantitative trait loci (QTLs) for agronomic traits under normal and drought stress conditions. Using the composite interval mapping, a total of 16 QTLs were identified for the studied traits in both conditions. We detected 8 QTLs located on chromosomes 1, 3, 4, 8 and 9 in the non–stress condition. Favorable alleles were contributed by Spidroud for straw weight and grain number. Under drought condition, several QTLs were identified which were located on chromosomes 1, 2, 4, 5, 6, 9 and 10. Among the detected QTLs, 6 explained more than 20% of the phenotype variation.

In this study, SRAP molecular maker approach was performed to investigate genetic diversity in the Salvia genus. A total of 205 DNA bands were produced from PCR amplification of 11 Salvia species and populations using 25 selective primer combinations, of which 204 polymorphic genetic loci accounted. The total number of amplified fragments ranged from 3 to 15. The genetic similarities of 11 collections were estimated from 0.0968 to 0.6949. According to the SRAP marker analysis, S.verticillata2 and S.nemorosa2 had the lowest similarityand the species of S.verticillata2 and S.verticillata3 had the highest similarity. Unweighted pair-group method with arithmetic averages clustering algorithm categorized Salvia species into six major groups. In general, SRAP markers were able to detect high polymorphism among Salvia genotypes. Hence, the technique is regarded as a reliable tool for differentiation of Salvia at inter and intra-species level.