镁肥对水稻镁吸收与分配及稻米食味品质的影响

Effects of Mg Fertilization on Mg Uptake and Partition by Rice and Rice Cooking Quality

以‘宁粳2号’为材料，采用田间小区试验方法研究了单季粳稻施用镁肥后对镁吸收分配的影响。结果表明，从拔节到始穗期，水稻体内镁的阶段吸收量和吸收速度最高，分别为7．22kg·hm^-2和0．40kg·hm^-2·d^-1；从拔节期到齐穗期，镁肥的施用促进了水稻对镁的吸收，其它生育期对外界镁浓度变化不敏感；镁肥的施用降低了镁在茎鞘和叶片中的分配比例，提高了镁在穗部的分配比例；齐穗后15～30d为穗部积累镁的高峰期；在本实验范围内，随施肥水平的提高，稻米中的镁含量升高，RVA（Rapid of viscosity analysis）谱中最终黏度、回复值及消减值显著下降，最高黏度、热浆黏度和崩解值显著上升，糊化温度没有明显差异。施用镁肥提高了稻米食味品质，这其中以120kg·hm^-2用量效果最好。

A plot experiment was conducted to study the effects of Mg fertilization on Mg uptake and parti- tion in single-cropping japonica rice with ＇Ningjing 2＇ as the material. It was shown that in the rice, the Mg-uptaking capacity and rate reached the highest from the jointing stage to the booting stage,separately amounting to 7.22 kg · hm^-2 and 0.40 kg · hm^-2·d^-1 ;Mg fertilization enhanced Mg uptake by the rice from the jointing stage to the full-heading stage and the rice was not sensitive to the change in external Mg concentration in the other developmental stages. Mg fertilization reduced the ratios of Mg allocated to the pedicle sheaths and the leaves and increased the ratios of Mg allocated to the spikes;the highest Mg accumulation appeared in the spikes 15-30 days after the full heading time;The experiment showed that as the fertilizer rate was increased the Mg content increased in the rice kernels and the final viscosity,consistence value,setback viscosity value in RVA significantly declined, while the peak viscosity, hot paste viscosity and breakdown value in RVA significantly increased,the gelatinization temperature in RVA did not show clear variation. Mg fertilization improved the cooking quality and the most favorable effect occurred at 120 kg · hm^-2 base fertilizer per hectare.