在热带和亚热带生态中,玉米产量和生产力受到干旱胁迫的影响。因为在这些生态系统中,玉米种植的大部分地区都是雨水灌溉的。本研究旨在研究24-表油菜素内酯(EBR)作为植物激素对玉米耐旱性的生理和生化影响。两个玉米杂交种,Vivek杂种9和Bio9637在三种不同的条件下生长:(i)灌溉,(ii)干旱,和(iii)干旱+EBR。开花前共2周,停止灌溉以产生类似干旱的条件。在干旱+EBR处理组中,灌溉也停止了,此外,EBR在干旱地块的同一天作为叶面喷雾施用。观察到干旱对光合作用速率有主要影响,膜稳定性指数,叶面积指数,相对含水量,和叶水势;这种影响在Bio9637中更为明显。相反,抗氧化酶的活性,如过氧化氢酶(CAT),抗坏血酸过氧化物酶(APX),在干旱条件下,两个杂种中的超氧化物歧化酶(SOD)都增加。具体来说,与对照相比,Vivek杂种9在干旱条件下显示出高74%的CAT活性。此外,与干旱条件下的植物相比,EBR的应用进一步将该酶的活性提高了23%。由于干旱胁迫,两种杂种的植物周长均显着降低。然而,发现外源应用EBR减少了干旱胁迫对植物的有害影响,这种影响在Bio9637中更为明显。事实上,在干旱条件下,与未处理的植物相比,用EBR处理的Bio9637显示脯氨酸含量增加了86%,甘氨酸甜菜碱含量增加了70%。一起来看,我们的结果表明EBR增强了玉米杂交种的耐旱性。因此,花前叶面施用EBR可能部分克服玉米开花期干旱的不利影响。
Maize production and productivity are affected by drought stress in tropical and subtropical ecologies, as the majority of the area under maize cultivation in these ecologies is rain-fed. The present investigation was conducted to study the physiological and biochemical effects of 24-Epibrassinolide (EBR) as a plant hormone on drought tolerance in maize. Two maize hybrids, Vivek hybrid 9 and Bio 9637, were grown under three different conditions: (i) irrigated, (ii) drought, and (iii) drought+EBR. A total of 2 weeks before the anthesis, irrigation was discontinued to produce a drought-like condition. In the drought+EBR treatment group, irrigation was also stopped, and in addition, EBR was applied as a foliar spray on the same day in the drought plots. It was observed that drought had a major influence on the photosynthesis rate, membrane stability index, leaf area index, relative water content, and leaf water potential; this effect was more pronounced in Bio 9637. Conversely, the activities of antioxidant enzymes such as catalase (CAT), ascorbate peroxidase (APX), and superoxide dismutase (SOD) increased in both hybrids under drought conditions. Specifically, Vivek hybrid 9 showed 74% higher CAT activity under drought conditions as compared to the control. Additionally, EBR application further enhanced the activity of this enzyme by 23% compared to plants under drought conditions. Both hybrids experienced a significant reduction in plant girth due to drought stress. However, it was found that exogenously applying EBR reduced the detrimental effects of drought stress on the plant, and this effect was more pronounced in Bio 9637. In fact, Bio 9637 treated with EBR showed an 86% increase in proline content and a 70% increase in glycine betaine content compared to untreated plants under drought conditions. Taken together, our results suggested EBR enhanced tolerance to drought in maize hybrids. Hence, pre-anthesis foliar application of EBR might partly overcome the adverse effects of flowering stage drought in maize.