Vigor and anaerobic metabolism of soybean seeds evaluated by ethanol test

Abstract: Among the vigor tests, ethanol is an alternative that provides desirable characteristics to be applied in seed-producing companies internal quality control planning. The aim was to evaluate the vigor of soybean seeds by the ethanol test and the fermentative metabolism after its application. A completely randomized experimental design with five replications was used, with treatments consisting of 10 lots of soybean seeds, except for the variables composing the fermentative metabolism, for which five lots of soybean seeds were used. First, the initial quality of the lots was assessed by evaluating water content, germination, seedling emergence, accelerated aging, tetrazolium test (vigor), electrical conductivity, and seed respiration. For the ethanol test, the seeds were subjected to soaking times of 30, 60, 90, and 120 minutes until the moment of reading, and subsequently, the fermentative metabolism was evaluated (lactate dehydrogenase - LDH, pyruvate decarboxylase - PDC, and alcohol dehydrogenase - ADH). The ethanol test in soybean seeds efficiently ranks lots into different levels of vigor, using the soaking time of 30 minutes, showing a moderate association between the electrical conductivity test and seed respiration. Furthermore, the activity of the enzymes LDH, PDC, and ADH proves that ethanol is produced during the soaking process of soybean seeds.

摘要：在各类种子活力测试（vigor test）方法中，乙醇测试（ethanol test）具备优异的应用特性，可适配种子生产企业的内部质量控制规划需求。本研究旨在通过乙醇测试法评估大豆种子的活力，并探究该测试处理后大豆种子的发酵代谢情况。本研究采用完全随机试验设计，设置5次重复；试验共使用10批大豆种子，但针对发酵代谢相关指标的测定，仅选取其中5批种子开展。首先，通过测定水分含量、发芽率、幼苗出苗率、加速老化试验、四唑测试（tetrazolium test，活力测定）、电导率以及种子呼吸速率，评估各批次种子的初始质量。针对乙醇测试，将种子分别浸泡30、60、90和120分钟后进行读数；随后测定其发酵代谢相关酶活性，包括乳酸脱氢酶（lactate dehydrogenase, LDH）、丙酮酸脱羧酶（pyruvate decarboxylase, PDC）以及乙醇脱氢酶（alcohol dehydrogenase, ADH）。采用30分钟浸泡时长的大豆种子乙醇测试法，可有效将种子批次划分为不同活力等级，且该测试结果与电导率测试、种子呼吸速率之间呈中等相关性。此外，LDH、PDC及ADH三种酶的活性验证了大豆种子浸泡过程中确实会产生乙醇。