结实期土壤水分对稻米品质的影响

Effects of Soil Moisture on Rice Quality during Grain-filling Period

以粳稻武香粳 9号和杂交籼稻汕优 6 3为材料 ,通过严格控制土壤水分的盆栽试验 ,研究了结实期土壤水分(土水势 )对稻米品质形成的影响。结果表明 :(1)水稻籽粒整个灌浆结实期间 ,当间歇灌溉的低限土水势为 - 15 k Pa时 ,整精米率提高 ,对垩白粒率和垩白度无显著影响 ,胶稠度变软 ,稻米品质有所改善 ;(2 )而当低限土壤水势≤ - 30k Pa时 ,整精米率显著降低 ,垩白粒率、垩白度显著提高 ,对胶稠度的影响表现二次曲线的关系 ,而对粒形、直链淀粉含量和粗蛋白影响较小 ,处理间差异不显著 ;(3)在籽粒灌浆期 ,不同土壤水分处理稻株的颖花绿叶量、叶绿素含量、籽粒含水量等生理指标有明显变化 ,低限土水势≤ - 30 k Pa,灌浆中后期 (花后 2 5～ 35天 )的颖花绿叶量和叶绿素含量的相对差值表现出明显的负效应 ,籽粒失水较快 ,从而影响米质形成期光合生产和籽粒中淀粉的积累 ,最终导致米质变劣 ,整精米率显著下降 。

With Wuxiangjing 9 (a japonica variety) and Shanyou 63 (an indica hybrid rice combination) as material, the effects of soil moisture (soil water potential) on the development of rice quality at filling stage were studied in the pot by rigorously controlling soil water potential with tensionmeters. The main results were as follows: (1) During the grain filling period, when the soil water potential (SWP) was reduced to -15 kPa, head milled rice was significantly increased, gel consistency become soft and no obvious effects on the percentage of chalky grain and chalkiness were observed; (2) While SWP was ≤-30 kPa, head milled rice was significantly decreased, both the percentage of chalky grain and chalkiness significantly increased. There was a conic relationship between gel consistency and SWP, and no significant difference among treatments in other quality indices, such as kernel shape, amylase and protein content, were found; (3) There were obviously changes in leaf to spikelet ratio, chlorophyll content and grain water content during grain filling period. If the low soil water potential was under -30 kPa, the relative dispersion of leaf to spikelet ratio and chlorophyll content were presented negative effects during the 25~35 days after flowering, dehydration of kernel was very rapid, which had an effect on both the production of photoassimilates and the accumulation of starch.