種子處理對人工老化苦瓜種子在次適溫下抗氧化反應之影響研究

Abstract

苦瓜屬於熱帶作物，低溫下會有發芽弱勢現象，本試驗使用水萌爆、硒萌爆及熱休克處理苦瓜種子來改善發芽弱勢問題，且將種子置於40 ℃，100 %相對溼度的環境中，加速種子之老化來研究種子耐貯性，並從抗氧化酵素的活性與同功異構表現型表現，可溶性與熱穩定性蛋白質電泳來探討影響種子活性之生理因素。試驗結果顯示水萌爆、硒萌爆及熱休克處理可增進種子在適溫與次適溫下的出土，其原因來自於抗氧化酵素活性增加與同功異構表現型的表現改變，而熱穩定性蛋白電泳圖譜的改變可能也是重要原因之一。經人工老化處理後的水萌爆、硒萌爆及熱休克種子於25 ℃的環境中出土，仍可維持其增進效果，但在20 ℃下則出現相當低的出土率，MDA與過氧化物累積嚴重，蛋白質含量降低，酵素活性降低同功異構表現型表現也不同，可溶性蛋白與熱穩定蛋白成分亦發生變異。

Bitter gourd is a tropical crop and poor germination is common at low temperature. In this study, bitter gourd seeds were subjected to priming, selenium priming, and heat shock to improve their germination responses. Moreover, treated seeds were also aged at 40℃ and 100﹪relative humidity conditions to investigate seed longevity, isoforms of anti-oxidative enzymes and heat stable protein responses. The results indicated that, in both 25 and 20 ℃ conditions, priming, selenium priming and heat shock treatments enhanced the emergence responses. These results might be due in part to the enhanced anti-oxidative activities and the modified isoforms expression. Nevertheless, the changes in soluble and heat stable soluble protein might also involve in these emergence improvements. At 25 ℃, primed, selenium and heat-shocked seeds receiving accelerate aging still maintained their emergence advantages over non-aged counterparts. However, at 20 ℃, all the treated seeds subjected to aging showed reduced emergence, increased MDA and total peroxides accumulations and protein degradation. The activities of anti-oxidative enzymes and the expression of isoform were also affected by accelerate-aging.