Effect of zinc nanoparticle on physiology of mungbean [Vigna radaita (L.) Wilczek] under normal and salinity stress condition
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Date
2020
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DRPCAU, Pusa
Abstract
About 20 per cent of the world’s cultivated area and approximately 50 % of the world’s irrigated lands are moved by salinity making it one of the main constraint for crop growth and production. As Mung bean is sensitive to salt stress and increasing salt concentration reduces its growth, development and yield attributes. On the other hand, potential of nanoparticles; in addition, the role of Zn in plant system as micronutrient, and the ZnO nanoparticle in agricultural research has suggested the possibility of zinc contribution in developing tolerance against the effect of stress.
The present study entitled “Effect of zinc nanoparticle on physiology of Mung bean [Vigna radiata (L.) Wilczek] under normal and salinity stress condition” was conducted with two objectives i.e. (1)To assess the effect of seed priming with zinc oxide nanoparticles on germination physiology and seedling growth of Mung bean genotypes under normal and
salinity stress condition. (2) To investigate the response of seed priming and foliar spray of zinc oxide nanoparticles on morpho-physiological and biochemical traits of Mung bean seedlings under normal and salinity stress condition. The emergence percent and seedling traits were evaluated in 10-days old seedlings under 1st objective and morpho-physiological and biochemical parameters were evaluated in 25-days old seedling under 2nd objectives in both salinity tolerant (TMB-37) and susceptible (MH-1314) genotypes of mung bean grown in pot condition under normal along with saline soil condition. In addition, dry matter and other growth paramters were also evaluated at harvesting stage i.e. 60 days after emergence in both genotypes under normal and saline soil condition.
Salinity significantly reduced emergence percent and seedling traits i.e. shoot length, root length, shoot dry weight, root dry weight, seedling length, vigour index-I, vigour index-II and SPAD value; However, the reduction percent was greater in susceptible genotype (MH-1314) as compared to tolerant genotype (TMB-37). Seed were primed with different concentration of ZnO nanoparticles i.e. T1 (50 ppm), T2 (100 ppm), T3 (250 ppm), T4 (500 ppm) and T5 (1000 ppm); where, emergence percent significantly increased with T1 and T2 in tolerant genotype, with T1, T2, T3, T4 and T5 in susceptible genotype under normal along with saline soil condition, significantly increased shoot length, shoot dry weight, seedling length, vigour index- I, vigour index –II and SPAD value with T1, T2, T3, T4 and T5 in both genotypes under normal along with saline soil condition. Similar was reflected for root length and root dry weight except root length of susceptible genotype and root dry weight of both genotypes which in contrast significantly decreased with T5 i.e. when treated with 1000 pm of ZnO nanoparticles under normal along with saline soil condition. However, maximum percent change was exhibited by seed priming with ZnO nanoparticles of T1 i.e. 50 ppm in both tolerant and susceptible genotypes under normal along with saline soil condition.
Salinity significantly affect morpho-physiological and biochemical parameters by reducing plant height, leaf area, specific leaf weight (SLW), dry matter of plant, relative water content (RWC), membrane stability index (MSI), photosynthetic pigments, chlorophyll stability index (CSI) and by increasing the lipid peroxidation; in this concern, the percent change was greater in susceptible genotype as compared to tolerant genotype. And also by increasing specific leaf area (SLA), antioxidant machinery i.e. superoxide dismutase activity (SOD), peroxidise activity (POX) and proline content; where, the percent increase was greater in tolerant genotype in contrast to susceptible genotype. In addition, salinity significantly reduced dry matter of plant and its other growth paramters also i.e. plant height,
leaf area and SLW and pod dry weight also. However, treatment with 50 ppm of ZnO nanoparticle with different methods i.e. T1 (seed priming with ZnO), T2 (foliar spray with ZnO) and T3 (seed priming + foliar spray with ZnO) significantly increased plant height, leaf area, SLW, dry matter of plant, RWC, MSI, photosynthetic pigments and CSI, significantly reduced lipid peroxidation and further increased SLA and antioxidant machinery i.e. SOD & POX and proline content in 25-days old seedling; in addition, also increased growth paramters (leaf area, SLW, pod dry weight etc) at harvesting stage in both genotypes under normal along with saline soil condition. However, optimum percent change in morpho-physiological and biochemical parameters, dry matter of plant and other growth paramters was exhibited by T3 (seed priming + foliar spray with 50 ppm ZnO NP) in both tolerant and susceptible genotypes under normal along with saline soil condition.
The study suggest optimum dose of ZnO nanoparticles (50 ppm) increased the tolerance against salinity stress by maintaining membrane stability, by decreasing lipid peroxidation and by further increasing in proline content and antioxidant enzymatic activity (SOD and POX). Overall, the study demonstrates that seed priming followed by foliar spray with optimum dose ZnO nanoparticle (50ppm) improved the plant growth of mung bean genotypes under normal along with saline condition. This signifies that optimum levels of ZnO nanoparticles improved cell metabolism leading to promote growth and stress tolerance.