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In this research, eight local mung bean (Vigna radiata) varieties were analyzed for their performance against two levels of CdCl2 solution (0.3 and 0.5 mM) alone and priming with gibberellic acid (GA3) (100 μM), salicylic acid (SA) (50 μM) and proline (5 mM) solution prior to Cd exposure. Mung bean seedlings were analyzed for disturbance in cytological, morphological, biochemical and enzymatic parameters under cadmium stress. For cytological studies, 48 h grown mung bean seedlings root tips were used to prepare slides and studied for percent mitotic index (MI%) and to calculate percent C-mitosis, laggard, sticky and fragmented chromosomes, pictures were captured by a Nikon camera (DS-Fi 1 Japan) attached with a microscope. One-week grown mung seedlings were studied for growth traits, malondialdehyde (MDA), protein, proline and antioxidant enzymes. ANOVA and DMR test of this research revealed that all the tested mung bean varieties and treatments were significantly different regarding mitotic index and number of chromosomal aberrations. Both the Cd treatments exhibited increased total chromosomal aberrations with different types and a maximum decrease in MI%. In pretreated samples, GA3, SA and proline serve as mitigating agents that reduce mutagenic effects of Cd in mung bean by increasing MI% and decreasing chromosomal aberrations as compared to non-pretreated samples. Both the Cd treatments showed a decrease in all growth traits. Total proteins were also found to be significantly reduced in a dose-dependent manner in all genotypes. Cd treatment increased the activities of all antioxidant enzymes tested. Cd caused oxidative damage as indicated by elevated levels of MDA content in treated samples in comparison to control. Proline content levels were also high in Cd treated seedlings indicating stress. Results demonstrated that pretreatment with phytohormones and proline before Cd were found to improve all morphological parameters, by altering antioxidant enzymes activities along with a decrease in MDA and proline contents as well. It was further noticed that the performance of GA3 was better at 0.3 mM Cd treatment while SA was found to be a good mitigating agent at 0.5 mM Cd stress in all tested mung bean varieties. This research concluded less deleterious effects of Cd on AZRI-2006 while more sensitivity to NM-51 towards Cd. Priming with phytohormones and proline is a user-friendly, economical, and simple mitigation strategy to reduce Cd toxicity in plants and get better yield from contaminated lands.

Plant photosynthesis and biomass production are closely associated traits but critical to unfavorable environmental constraints such as salinity and drought. The relationships among stress tolerance, photosynthetic mechanisms, biomass and ethanol yield were assessed in Phragmites karka. The growth parameters, leaf gas exchange and chlorophyll fluorescence of P. karka were studied when irrigated with the control and 100 and 300 mM NaCl in a nutrient solution and water deficit conditions (drought, at 50% water holding capacity). The plant shoot fresh biomass was increased in the low NaCl concentration; however, it significantly declined in high salinity and drought. Interestingly the addition of low salinity increased the shoot biomass and ethanol yield. The number of tillers was increased at 100 mM NaCl in comparison to the control treatment. High salinity increased the photosynthetic performance, but there were no significant changes in drought-treated plants. The saturated irradiance (Is) for photosynthesis increased significantly in low salinity, but it declined (about 50%) in high salt-stressed and (about 20%) in drought-treated plants compared to the control. The rates of dark respiration (Rd) and compensation irradiance (Ic) were decreased significantly under all treatments of salinity and drought, with the exception of unchanged Rd values in the control and drought treatments. A-Ci curve analyses revealed a significant improvement in the Jmax, Vc, max, and triose-phosphate utilization (TPU) at lower salinity levels but decreased at 300 mM NaCl and drought treatments compared to the control. In the chlorophyll fluorescence parameters (Fv/Fm, maximum photochemical quantum yield of PSII, and Y(NO)), the non-photochemical yields were not affected under the salt and drought treatments, although an effective photochemical quantum yield (YII) and electron transport rate (ETR) were significantly enhanced in water deficit compared to control plants. P. karka regulates an efficient photosynthesis mechanism to grow in saline and arid areas and can therefore be used as a sustainable biofuel crop.

ObjectivesThe high salinization stress to seedling is the substantial ecological problem in the ongoing era. It negatively influences the growth that retard mitotic division by enhancing aberrations in nuclear chromatin. In the light of these views, the current work was designed to investigate the response of Vigna seedlings root tip cells to the presence of NaCl ions.Materials and methodsNM-92 and NM19-19 seeds were imbibed separately in distilled water for 24 h and allowed to grow into 0, 50, 150, 250, and 350 mM NaCl solution for 24 h. Excised root tips were stained, and slides were scored at 100× objective for the mitotic index (MI) and chromosomal aberrations.ResultsOur data demonstrated that as NaCl molarity increased, the MI was declined along with various chromatin abnormalities. The 150 mM of NaCl showed more lagging (69%) of chromosomes during anaphase in NM19-19. The highest stickiness at metaphase stage (68%) was found in 250 mM NaCl in variety NM19-19. However, both varieties were differed non-significantly for c-mitosis that was recorded 99% at 350 mM NaCl concentration.ConclusionsThe NaCl ions toxicity induced various cytological anomalies in seedling roots that adversely affect the growth of Vigna seedlings.

Due to urbanization and industrialization, heavy metals have become the common environmental pollutant throughout the world. Chromosomal studies are one of the important tools to estimate the genome damaging property of these metals. This research was done to analyze the genotoxic effects of metals such as cadmium (Cd), nickel (Ni), mercury (Hg), lead (Pb) and copper (Cu) in mung bean (Vigna radiata) root tips. The experiment was set in such a way that mild metal treatment (0.01 mM) was given before respective high metal treatments (0.1 and 0.5 mM) separately, with the aim to know whether low/mild metals can alleviate metal tolerance in mung bean seedlings. Results demonstrated that metals treatment resulted in growth and mitotic index reduction. Among all the tested metals, Cd was found to cause more negative effect on growth of mung bean seedlings with length of 6.12 cm and 13.41% mitotic Index (MI) with the highest total aberrations (27.91%) at 0.5 mM Cd. Positive correlation was found between mitotic index and seedling length while a negative correlation was recorded between chromosomal aberrations with mitotic index and seedling length. Among these abnormalities C-mitosis, sticky chromosomes, and disturb metaphase were the most common aberrations irrespective of the metal. Furthermore, it was also observed that seed priming with respective mild metal concentration improves the seedling length, MI, and reduces the effect of metal stress by lowering the chromosomal aberrations in both 0.1 mM and 0.5 mM concentrations as compared to metal stress alone.