ANTIOXIDANT DEFENSES OF IRRIGATED FORAGE SORGHUM WITH SALINE AQUACULTURE EFFLUENT

ABSTRACT The objective of this work was to evaluate the biomass production and antioxidant enzymatic system activity of irrigated forage sorghum with saline aquaculture effluent under different leaching fractions. The experiment was conducted in the Caatinga Experimental Field of the Embrapa Semiarido, in Petrolina, State of Pernambuco, Brazil. The experimental design was a complete randomized block in a split-plot arrangement with four replications, consisting of three forage sorghum varieties (Volumax, F305 and Sudan) and four leaching fractions (0, 5, 10 and 15%). The vegetal materials were collected when the plants were at the soft-dough stage. The biomass production and activity of the enzymes superoxide dismutase, catalase and ascorbate peroxidase were evaluated. Irrigation with saline aquaculture effluent with leaching fraction of 15% results in low salinity level in the root zone and higher biomass production of forage sorghum Sudan and F305, in semiarid conditions. The antioxidant system was activated in the three sorghum varieties to prevent accumulation of reactive oxygen species, with the synchrony between the enzymes superoxide dismutase and catalase resulting in a better productive response of the varieties Sudan and F305.

摘要
本研究旨在评估不同淋洗分数（leaching fractions）下，采用水产养殖盐水尾水灌溉的饲用高粱（forage sorghum）的生物量产量与抗氧化酶系统（antioxidant enzymatic system）活性。试验于巴西伯南布哥州佩德罗利纳市的巴西农业研究公司半干旱研究所（Embrapa Semiarido）卡廷加试验田开展。试验采用随机完全区组裂区设计，设置4次重复，供试处理包含3个饲用高粱品种（Volumax、F305、苏丹（Sudan））与4个淋洗分数（0、5%、10%、15%）。供试植株于软面团期（乳熟末期）进行采样，测定了植株生物量产量以及超氧化物歧化酶（superoxide dismutase）、过氧化氢酶（catalase）与抗坏血酸过氧化物酶（ascorbate peroxidase）的活性。
在半干旱环境下，采用淋洗分数为15%的水产养殖盐水尾水灌溉，可使根区盐分维持在较低水平，同时提升苏丹（Sudan）与F305饲用高粱的生物量产量。三个高粱品种均激活抗氧化系统以抑制活性氧物种（reactive oxygen species）积累，其中超氧化物歧化酶与过氧化氢酶的协同作用可使苏丹（Sudan）与F305品种获得更优的生产表现。