吐丝期施氮对夏玉米粒重和籽粒粗蛋白的影响

Effect of Additional N Supplied at Silking on 1 000-Grain Weight and Grain Crude Protein Content of Summer Corn

以中晚熟高产玉米品种农大108为供试材料,分别研究了在前轻中重(基肥N90kg·hm-2++小花肥N 180 kg·hm-2)和前重中轻(基肥N 180 kg·hm-2++小花肥N90kg·hm-2)共2种氮肥运筹基础上均于吐丝期增施N 75 kg·hm-2对籽粒灌浆和籽粒N积累的影响。结果表明:1)吐丝期增施氮肥后籽粒千粒重明显增加(4.81%)且接近显著水平,其中在前轻中重基础上吐丝期施氮后烘干千粒重比原来(257.7g)提高5.89%;2)吐丝期增施氮肥显著地提高了籽粒粗蛋白含量,如在前重中轻基础上籽粒粗蛋白含量由原来的7.63%增加到 8.23%(增幅达 7.95%);3)吐丝期增施氮能使籽粒产量增加 5.38%,尤其是在前轻中重基础上增施氮后产量比原来(9 615kg·hm-2)增加 7.61%且达显著水平。本文认为吐丝施氮显著提高了籽粒第二灌浆峰值,使得籽粒可溶性糖含量在灌浆前期得到明显提高并在灌浆中后期维持在一定水平;明显地促进了灌浆中后期籽粒氮的积累,使得籽粒含氮量在灌浆中后期一直维持在较高水平,这可能是玉米获得较高籽粒产量和籽粒品质的生理基础。

To study the effect of additional N supplied at silking (ANSS) on grain filling and grain N accumulation, field experiment with four treatments and one mid-late maturity hybrid Nongda108 was carried out at Wuqiao experimental station of CAU in 2000. Based on two N application strategy consisting of 12(1/3 of N 270 kg·hm-2 at basal and the rest at + floret) and 21(2/3 of N 270 kg·hm-2 at basal and the other at + floret), additional N 75 kg·hm-2 at silking (i. e. 12+and 21+, respectively) and none additional N at silking (i. e. 120 and 210, respectively) comprise these four treatments. Field trial's results showed that: 1) In comparison with none N supplied at silking (NNSS), ANSS dramatically elevated the 2nd filling climax value and increased 1 000-grain weight, and e.g. the 1 000-grain wt. of 12 + was higher than that of 120 by 5. 89%; 2) Grain N accumulation during mid-late phase of filling was promoted by ANSS. Grain crude protein concentration of 21+at maturity was more than that of 210 by 7. 95%; and 3) The grain yield of ANSS was higher than that of NNSS by 7. 61%. It has been suggested that the higher concentration of water soluble sugar during early-phase of filling but lower during late-phase of filling than total N would be beneficial to grain carbohydrate accumulation and protein synthesis.