Isoenzyme activity in maize hybrid seeds harvested with different moisture contents and treated

Abstract: The analysis of isoenzyme activity is an important monitoring and characterization tool of the physiological quality of seeds and to understand the deterioration. The purpose of this work was to study the isoenzyme expression allied to the quality of maize hybrid seeds harvested at different moisture levels and subjected to chemical treatment. A completely randomized experimental design was used with four replicates, in a 3x2 factorial arrangement with three moisture levels (45%, 40% and 35%), and two forms of seeds tillage (with and without treatment). Seeds from maize hybrids, semi-hard BM 810 and dented BM 3061, were used. Seeds were manually gathered on ears. Chemical treatment was performed with commercial products Maxin(r) + K-obiol(r) + Actellic(r). Seed quality was assessed by moisture test, incidence of mechanicals damage, first count of germination, germination, emergence, emergence speed index, mean emergence time, accelerated aging, and electrical conductivity. Isoenzyme expressions were assessed by means of the systems superoxide dismutase (SOD), catalase (CAT), esterase (EST), alcohol dehydrogenase (ADH), malate dehydrogenase (MDH), peroxidase (PO) and α-amilase. Isoenzyme expressions are different, depending on moisture levels at harvest, the hybrid maize and seeds quality. Seeds treatment does not interfere in their isoenzymes expression.摘要：同工酶活性分析是监测、表征种子生理品质并解析种子劣变机制的重要工具。本研究旨在探究不同收获含水率条件下、经化学处理的玉米杂交种种子的同工酶表达特征及其与种子品质的关联。本实验采用完全随机设计，设置4次重复，采用3×2因子排列，包含3个收获含水率水平（45%、40%与35%）以及2种种子处理方式（经化学处理与未经处理）。实验所用材料为半硬粒型玉米杂交种BM 810与马齿型玉米杂交种BM 3061，种子均从果穗上人工采收。化学处理采用市售药剂Maxin®、K-obiol®与Actellic®复配进行。种子品质通过以下指标进行评价：含水率测定、机械损伤发生率、发芽势、发芽率、出苗率、出苗速率指数、平均出苗时间、加速老化试验以及电导率测定。同工酶表达特征通过以下酶系统进行检测：超氧化物歧化酶（superoxide dismutase, SOD）、过氧化氢酶（catalase, CAT）、酯酶（esterase, EST）、乙醇脱氢酶（alcohol dehydrogenase, ADH）、苹果酸脱氢酶（malate dehydrogenase, MDH）、过氧化物酶（peroxidase, PO）以及α-淀粉酶（α-amylase）。研究结果表明，同工酶表达特征因收获含水率、玉米杂交种类型以及种子品质而异；种子化学处理并不会对其同工酶表达产生影响。