PRIMING OF BRACHIARIA SEEDS WITH DIFFERENT SUGAR SOURCES AND CONCENTRATIONS

ABSTRACT Seed priming is a practice for improving the expression of seed physiological potential. Such technique consists of synchronizing and reducing the time of seed germination by controlled hydration. The aim of this study was to evaluate the effect of seed-priming with different sugar sources and concentrations on the physiological quality Urochloa brizantha seeds and initial seedling performance. Before treating, seeds were scarified chemically with concentrated sulphuric acid (H2SO4) for 5 minutes to overcome physical dormancy. The experimental design was completely randomized in a 3 x 6 factorial scheme consisting of priming using three sugar sources (glucose, sucrose, and maltose) and six concentrations (zero [water control], 2%, 5%, 10%, 15%, and 20%), with four replicates. The seeds were primed by direct immersion for 2 hours at 25 ºC and, after hydration, they were dried for moisture equilibrium recovery. Seed germination, vigor, viability, and initial seedling growth were evaluated. The results showed that glucose was the source able to promote beneficial effects on the germination of U. brizantha cv. MG-5 seeds. Moreover, the supply of glucose at the concentrations of 2 and 5% for physiological conditioning increased seedling dry phytomass.

摘要 种子引发（seed priming）是一项可提升种子生理潜力表达的技术，该技术通过受控水合作用实现种子萌发的同步化并缩短萌发周期。本研究旨在探究不同糖源及浓度的种子引发处理对臂形草（Urochloa brizantha）种子生理品质及幼苗初期生长性能的影响。试验前，为破除种子的物理休眠，采用浓硫酸（H₂SO₄）对种子进行5分钟化学酸蚀处理。试验采用完全随机设计的3×6因子方案，设置3种糖源（葡萄糖、蔗糖、麦芽糖）与6种浓度梯度（空白对照[去离子水]、2%、5%、10%、15%、20%），每组设置4次生物学重复。将种子置于25℃下直接浸种2小时完成引发处理，水合后将其干燥至水分恢复至平衡状态。本试验测定了种子萌发率、活力、生活力及幼苗初期生长情况。结果表明，葡萄糖可有效改善臂形草MG-5栽培品种（Urochloa brizantha cv. MG-5）的种子萌发表现；此外，采用2%与5%浓度的葡萄糖进行生理引发处理，可显著提升幼苗干物质积累量。