环扎对沙田机生理落果期间内源激素水平和碳水化合物含量的影响

研究了环扎处理对沙田柚生理落果期间新梢叶片和幼果的可溶笥碳水化合物含量和内源激素水平的影响。结果表明：环扎处理提高新梢叶片和幼果的可溶性碳水化合物含量。环扎处理明显减少新梢叶片IAA、GA1＋3、CTKs含量和（IAA＋GA1＋3＋CTKs）／ABA比值。叶片中IAA、GA1＋3、CTKs等激素含量的减少，反映新梢的库竞争能力降低。沙田柚果实IAA含量在生理落果期间有2次高峰，环扎处理的果实仅在初期有－IAA峰，且低于对照。环扎处理改变果实赤霉素变化曲线，GA1＋3高峰出现时间推迟，且较对照高，环扎后果实CTKs水平高于对照，在生理落果中后期有2胪明显高峰。环扎所导致的新梢生长受到抑制，座果率提高等生理效应可能与环扎后叶片中IAA、GA1＋3、CTKs等激素含量降低和果实中赤霉素、细胞分裂素含量提高有关。

Influence of Trunk Strangulation on Endohormone Levels and Carbohydrate Content During Physiological Fruit Drop Period in ''''Shatian'''' Pomelo

Effects of trunk strangulation on soluble carbohydrate and endohormone contents in flush leaves and young fruits of 'Shatian' pomelo during physiological fruit drop period were studied. The results showed trunk-strangulation treatment increased soluble carbohydrate content in leaves and young fruit. Trunk-strangulation treatment significantly decreased IAA, GA1 3, CTKs contents and (IAA GA1 3 CTKs)/ABA ratio in leaves. The reduction of IAA, GA1 3 and CTKs contents in leaves indicated the decline of sink competition strength of new shoots. 'Shatian' pomelo fruit without trunk treatment had two peaks of IAA content during physiological fruit drop period. while the fruit with trunk strangulation only had one IAA peak which was lower than that of the control. Trunk-strangulation treatment changed fruit GAs curve with a delayed GA1 3 peak which was higher as compared with the control. The fruit with trunk strangulation had higher CTKs level than the control and showed two peaks of CTKs content at the mid-late stage of physiological fruit drop. The inhibition of new shoot growth, improvement of fruit-set and other physiological effects caused by trunk strangulation were related with the decrease of IAA, GA1 3, CTKs contents in leaves and the increase of GA1 3, CTKs contents in fruits.