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The present study was conducted with the aim to isolate, characterize, and identify the promising zinc-solubilizing rhizobacteria found naturally in the rhizosphere of canola (Brassica napus L.) plants. The study investigated the roles of these strains in nutrient acquisition and assimilation of extracellular molecules such as hormones and secondary metabolites. Ten isolated promising zincsolubilizing strains (CLS1, CLS2, CLS3, CLS6, CLS8, CLS9, CLS11, CLS12, CLS13, and CLS15) were selected and characterized biochemically. Almost all the tested strains were Gram-positive, could fix nitrogen, and were positive for indole acetic acid, HCN, exopolysaccharides, and siderophore production. These effective zinc-solubilizing strains were identified through 16S rRNA gene sequencing. Based on the amount of solubilized zinc and halo zone diameter, four potent strains (CLS1, CLS2, CLS3, and CLS9) were selected for pot and field evaluation. Among all the identified bacterial genera isolated from the rhizosphere of the same host plant at different sampling sites, Priestia aryabhattai was found most abundant and found at all three sampling sites. The strains Priestia megaterium, Staphylococcus succinus, and Bacillus cereus were found at two different sites. Bacillus subtilis was found at only one site. These strains have a number of plant growth-stimulating characteristics as well as the ability to colonize plant roots successfully. The results indicated that inoculation of all these four zinc-solubilizing tested strains enhanced the plant growth, oil contents, and yield attributes of canola as compared to non-inoculated control with fertilizer levels. Staphylococcus succinus (CLS1) was first reported as a zinc solubilizer and associated with canola. Priestia aryabhattai (CLS2) and Priestia megaterium (CLS9) were found to be the best strains, with the most pronounced beneficial effect on canola growth and yield traits in both pot and field conditions. The sitespecific dominance of these strains observed in this study may contribute toward decision-making for the development of specific inocula for canola. Therefore, identification of these strains could help in providing adequate amount of soluble zinc along with enhanced plant growth, yield, and oil content of canola. [ABSTRACT FROM AUTHOR]

Under the current climate change scenario, water stress is one of the key factors that reduce the production of crops. Gibberellic acid (GA3) is an efficient endogenous plant hormone that shows a vital role in plant growth and development. Production of canola (Brassica napus L.) and its oil contents are severely affected under drought stress. The present study was conducted to investigate the potential of GA3 in alleviating drought stress in canola. Three levels of GA3 (G0 = 0 mg L−1, G1 = 100 mg L−1, and G2 = 150 mg L−1) as foliar applications were applied under two drought-stress conditions (D1 for three days of drought stress and D2 for six days of drought stress) on two canola varieties (Punjab canola and Faisal canola). Irrigation was applied after 3 weeks of germination, while foliar application of GA3 was done at intervals of 4 and 5 weeks after germination. When comparing the output of all the GA3 treatments, it was noticed that in G0 = 0 mg L−1 (control plants), water-stress conditions markedly reduced plant production and seed oil contents but increased protein and linoleic acid. With the application of G2 = 150 mg L−1, the maximum values of plant height (90.83 cm), no. of siliqua plant−1 (15.50), seed siliqua−1 (15.55), siliqua length (5.08 cm), relative water contents (77.60%), yield plant−1 (0.46 g), chlorophyll a (0.62), carotenoid contents (39.52), and oleic acid contents (60.20) were recorded under drought stress. Based on these results, it is concluded that the adverse effect of drought stress on different yield parameters of canola could be ameliorated by the exogenous application of GA3 through foliar application at a dose of 150 mg L–1. Moreover, the same treatment improves the quality parameters, i.e., the oleic acid contents of the oil, obtained from the canola. [ABSTRACT FROM AUTHOR]

Drought is key abiotic stress that reduced crop growth, development and yield. While several physiological processes are played role in plant adaptations to drought stress. However, antioxidant defense system and lipid peroxidation play a key role in drought tolerance. The current study was intended to investigate physiological adaptations for drought tolerance in different wheat varieties. Three weeks old seedlings of each wheat cultivar were challenged with drought stress by skipping irrigation. After the drought stress of two weeks, plants were subjected to morphological, biochemical and physiological investigations. Drought stress reduced the biomass and enhanced the root length in all three wheat varieties. However, growth reduction due to drought stress was relatively lower in variety F23. While the shoot length of all three wheat varieties was decreased because of drought stress, whereas the root/shoot ratio was increased. The root length was higher in variety F23. The chlorophyll a and b were decreased due to water shortage. Variety Pu19 had greater chlorophyll contents in comparison to other wheat varieties in drought conditions. The total soluble proteins, proline, glycinebetaine and phenolic contents were improved in all three wheat varieties under drought stress. The variety Pu19 was exhibited a higher level of proline, glycine betaine and phenolic contents were. Similarly, hydrogen peroxide (H2O2) and malondialdehyde (MDA) were improved in all three wheat varieties but this increase was relatively lower in variety F23. The superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) activities were improved in all wheat varieties in a water shortage. The variety F23 exhibited higher antioxidants levels which are positively associated with its potential of drought stress tolerance. This study provided a helpful understanding of the significant role of the antioxidant defense system of wheat crop especially the variety F23 in drought stress tolerance. [ABSTRACT FROM AUTHOR]

Salinity is a major abiotic stress that reduces the plant productivity. The plant growth promoting rhizobacteria (PGPRs) play important role in eliminating the effect of salinity. Cicer arietinum L. is an important legume crop having high quantity of proteins. In the present study, four varieties (CM44, CM91, CM98 and CM2000) were grown in the presence and absence of PGPR inoculated media and nitrogen in different salinity levels (20, 50, 100, 200 and 300mM NaCl). The biomass production of the varieties CM91 and CM98 increased at 20-100mM NaCl concentrations but drastically decreased at higher levels. While in varieties CM44 and CM2000 a gradual decrease of biomass with increasing salinity levels were observed. Number of pods, flowers and fresh weight of pods were not affected at salinity levels of 0-50mM and decreased at 100 mM NaCI in all the four varieties. In varieties CM91 and CM2000 nodules were formed at all levels of salinity treatments, while in varieties CM44 and CM98 nodules were formed at salinity levels of 0-50 mM NaCl and completely inhibited at 100mM NaCl. The total protein and nitrogen contents increased with concurrent increasing levels of NaCI. The plants treated with 50 mM NaCI had maximum amount of protein contents as compared to those at 0mM NaCI level. Varieties CM91 and CM2000 had higher protein contents than CM44 and CM98. At I/50 level of salinity the total protein contents were found more than inoculated control at 0mM NaCI. From this study, it is concluded that PGPRs can play an important role to mitigate the salt stress at different concentrations for better crop yield. [ABSTRACT FROM AUTHOR]

Salinity is a major soil problem limiting plant growth and development. Application of plant growth promoting rhizobacteria (PGPR) is effective against this stress. Mung bean is an important crop that is used as food. Present experiment was conducted under natural environment to evaluate the effect of PGPR on biomass production, nitrogen and proteins percentage of four mung bean varieties under different NaCI levels in sand culture after 5,7 and 9 weeks of sowing. Both inoculated and uninoculated plants were grown on mineral medium that were N-free either without NaCI or with a range of NaCI (20, 50,100, 200 and 300mM). Dry weight of plants was increased at 0-50mM NaCl and decreased at 100-300mM NaCI concentration. Inoculation effectively increased the dry weights of plants at salinity levels of 0-50 mM NaCI as compared to uninoculated plants but was not effective at 200-300mM NaCI. Number and fresh weight of pods were not affected at 0-100 mM NaCI levels of salinity but strongly decreased at 200-300 mM NaCl. Number and fresh weights of nodules increased slightly at lower levels (20-I00 mM) of salinity but strongly decreased at 200 mM NaCI. Nodulation and pods were completely inhibited at 300mM NaCl. The nitrogen percentage was decreased in salinity stress. The total protein contents increased with increasing levels of NaCI concentration. The plants in 50 mM NaCI maintained maximum amount of protein contents as compared to those at 0mM NaCI level. Varieties MI and NM92 had higher protein contents than M6 and NM98. From these findings it is concluded that PGPR can play an effective role in increasing crop production in saline soil. [ABSTRACT FROM AUTHOR]

A comparative study of stem epidermis of fourteen sugarcane varieties (i.e., L-l18, CP72-2086, CP43-33, HSF-240, CPF-237, SPF-213, COjv-84, CO-1148, COL-54, COL-29, CO-975, BL-4, Triton and BF-162) was carried out using Schultz's maceration method followed by staining with chloloiodide of Zinc. The results indicated substantial differences among the sugarcane varieties for various stem epidermal cell combinations and structures like number of stomata, number and shape of cork, silica, long, and pointed elongated cork cells. It is therefore contended that the structure of the epidermis in sugar cane can be used as a characteristic of variety differentiation. [ABSTRACT FROM AUTHOR]