蔗糖减缓水稻灌浆期高温对同化物转运抑制作用的原因分析

Sucrose Alleviates Inhibition on the Kernel Weight and Assimilation Distribution Caused by Heat Stress at Grain Filling Stage of Rice

以早籼稻浙辐802及其近等基因系fgl为材料,采用盆栽试验,于籽粒灌浆期在人工气候箱进行高温处理10 d(40℃/30℃,昼夜),研究高温下喷施蔗糖溶液对水稻结实率、千粒重和干物质积累及分配的影响。结果表明,籽粒灌浆期高温胁迫对结实率的影响较小,但千粒重显著下降,其中,浙辐802下降的幅度显著高于fgl。蔗糖在一定程度上可减轻高温胁迫对水稻粒重及同化物转运的抑制作用。高温下,蔗糖处理的千粒重显著高于对照,籽粒面积、周长及长度均高于对照。高温下,蔗糖对水稻植株同化物积累影响不大,但显著提高同化物在穗部的比例,即高温下蔗糖处理穗部干物质积累比例显著高于对照。鉴于此,笔者认为,蔗糖减轻籽粒灌浆期高温胁迫抑制的作用,主要在于影响同化物转运而不在于干物质积累。

A indica rice Zhefu 802 and its near-isogenic line fgl were subjected to high temperature conditions at 40℃/30℃(day/night)for 10 d at grain filling stage.The rice plants was sprayed with 2.5%sucrose before heat stress imposed.The results indicated that heat stress at grain filling stage had less effect on seed setting rate,but reduced the kernel weight in both rice varieties significantly,which accompanied with lower ratio between panicle dry weight and total dry weight,rather than the dry matter weight accumulation.Rice plants treated with sucrose attained significantly higher kernel weight than that of H2O treatment under heat stress in both rice varieties.Similarly,the ratio between the panicle dry matter and total plant dry matter of the sucrose treatment was significantly higher than those of plants treated with H2O under heat stress.This suggested that sucrose could alleviate the damages on the kernel weight and assimilate distribution by heat stress at grain filling stage.