Multiple stresses on the oxidative metabolism of sugarcane varieties

ABSTRACT: The exposure of plants to multiple stress conditions can cause over production of reactive oxygen species promoting an imbalance in the redox system. The aim of this study was to examine the antioxidant response from varieties of sugarcane under adverse conditions, to understand the defense mechanisms of tolerant and sensitive genotypes. Micropropagated sugarcane of six genotypes, RB966928, RB98710, RB855453, RB99395, RB867515, and RB855156, were subjected to isolated action of high-temperature stress and a combination of water and saline stress, and effects were evaluated. Activities of enzymes such as superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX), as well as stress indicators such as lipid peroxidation (MDA content) and hydrogen peroxide (H2O2) content were evaluated. The RB867515 variety showed synchrony between the enzymatic activity and ROS regulation and detoxification, in the plant cell under environmental stress situations, thereby ensuring the maintenance of the relative water content without increment of lipid peroxidation; and consequently, the maintenance of physiological processes and plant growth. These results indicated that lipid peroxidation associated with relative water content can be good biochemical markers of sensitivity to multiple stresses in sugarcane.

摘要：植物遭受多重胁迫时，会产生活性氧（reactive oxygen species, ROS）过量积累，引发氧化还原系统失衡。本研究旨在探究逆境条件下不同甘蔗品种的抗氧化响应，以解析耐性与敏感基因型的防御机制。实验选取6个基因型的组培甘蔗RB966928、RB98710、RB855453、RB99395、RB867515及RB855156，分别施加单一高温胁迫以及水分与盐复合胁迫，并对其胁迫效应进行评估。本研究测定了超氧化物歧化酶（superoxide dismutase, SOD）、过氧化氢酶（catalase, CAT）、抗坏血酸过氧化物酶（ascorbate peroxidase, APX）等抗氧化酶活性，同时检测了脂质过氧化水平（丙二醛MDA含量）、过氧化氢（H₂O₂）含量等胁迫相关生理指标。结果显示，RB867515品种在环境胁迫下，其酶活性与ROS调控及清除过程保持同步，可维持植株相对含水量，且未出现脂质过氧化水平上升，进而保障了生理过程与植株生长的稳定。本研究结果表明，脂质过氧化水平结合相对含水量，可作为甘蔗应对多重胁迫敏感性的优良生化标记物。