背景:硼(B)是一种微量营养素,但是过量会导致植物毒性,增长受损,减少光合作用。B毒性来自过度受精,高土壤B水平,或用富含B的水灌溉。相反,硅(Si)被认为是减轻压力和减轻某些营养素的毒性作用的元素。在这项研究中,为了评价不同浓度硅对硼胁迫条件下玉米的影响,基于随机完全区组设计的析因实验在水培系统中重复三次.实验采用玉米营养液。包含三种不同硼(B)浓度(0.5、2和4mgL-1)和三种Si浓度(0、28和56mgL-1)的优点。
结果:我们的发现揭示了外源施用B导致玉米叶片中B浓度的大幅增加。此外,B暴露引起新鲜和干燥植物生物量的显着减少,叶绿素指数,叶绿素a(Chla),叶绿素b(Chlb),类胡萝卜素,和膜稳定性指数(MSI)。随着B浓度的增加,丙二醛(MDA)含量和过氧化氢酶(CAT)活性伴随增加。相反,Si的补充促进了植物鲜重和干重的改善,总碳水化合物,和总可溶性蛋白质。此外,抗氧化酶活性的升高导致过氧化氢(H2O2)和MDA含量的降低。此外,Si和B的联合影响对叶片叶绿素指数有统计学意义,总叶绿素(a+b)含量,Si和B的积累水平,以及愈创木酚过氧化物酶(GPX)的酶活性,抗坏血酸过氧化物酶(APX),和H2O2水平。这些独特的发现表明B毒性对玉米的各种生理和生化属性的有害影响,同时强调了补充Si通过调节抗氧化剂机制和生物分子合成来减轻有害影响的潜力。
结论:这项研究强调了补充Si在减轻玉米中B毒性的有害影响方面的潜力。增加的Si消耗减轻了B毒性下的叶绿素降解,但它也导致必需微量营养素铁(Fe)的浓度显着降低,铜(Cu),和锌(Zn)。虽然补充Si在抵消B毒性方面显示出希望,观察到的Fe减少,Cu,和锌浓度值得进一步研究以优化这种方法并保持整体植物营养状况。
BACKGROUND: Boron (B) is a micronutrient, but excessive levels can cause phytotoxicity, impaired growth, and reduced photosynthesis. B toxicity arises from over-fertilization, high soil B levels, or irrigation with B-rich water. Conversely, silicon (Si) is recognized as an element that mitigates stress and alleviates the toxic effects of certain nutrients. In this study, to evaluate the effect of different concentrations of Si on maize under boron stress conditions, a factorial experiment based on a randomized complete block design was conducted with three replications in a hydroponic system. The experiment utilized a nutrient solution for maize var. Merit that contained three different boron (B) concentrations (0.5, 2, and 4 mg L-1) and three Si concentrations (0, 28, and 56 mg L-1).
RESULTS: Our findings unveiled that exogenous application of B resulted in a substantial escalation of B concentration in maize leaves. Furthermore, B exposure elicited a significant diminution in fresh and dry plant biomass, chlorophyll index, chlorophyll a (Chl a), chlorophyll b (Chl b), carotenoids, and membrane stability index (MSI). As the B concentration augmented, malondialdehyde (MDA) content and catalase (CAT) enzyme activity exhibited a concomitant increment. Conversely, the supplementation of Si facilitated an amelioration in plant fresh and dry weight, total carbohydrate, and total soluble protein. Moreover, the elevated activity of antioxidant enzymes culminated in a decrement in hydrogen peroxide (H2O2) and MDA content. In addition, the combined influence of Si and B had a statistically significant impact on the leaf chlorophyll index, total chlorophyll (a + b) content, Si and B accumulation levels, as well as the enzymatic activities of guaiacol peroxidase (GPX), ascorbate peroxidase (APX), and H2O2 levels. These unique findings indicated the detrimental impact of B toxicity on various physiological and biochemical attributes of maize, while highlighting the potential of Si supplementation in mitigating the deleterious effects through modulation of antioxidant machinery and biomolecule synthesis.
CONCLUSIONS: This study highlights the potential of Si supplementation in alleviating the deleterious effects of B toxicity in maize. Increased Si consumption mitigated chlorophyll degradation under B toxicity, but it also caused a significant reduction in the concentrations of essential micronutrients iron (Fe), copper (Cu), and zinc (Zn). While Si supplementation shows promise in counteracting B toxicity, the observed decrease in Fe, Cu, and Zn concentrations warrants further investigation to optimize this approach and maintain overall plant nutritional status.