夏玉米籽粒胚乳细胞增殖及产量对不同光照的响应

为了探讨不同光照条件对夏玉米籽粒胚乳细胞增殖及产量的影响,2012—2014年于山东农业大学试验农场进行了大田试验,选玉米品种郑单958和登海605为试验材料,设置大田自然光照(CK)、开花至收获期遮阴(S1)、拔节至开花期遮阴(S2)、出苗至收获期遮阴(S3)和开花至收获期增光(L)5个处理,研究其对夏玉米籽粒胚乳细胞增殖、籽粒灌浆、淀粉含量、干物质积累及产量的影响。结果表明,遮阴后籽粒胚乳细胞增殖速率、细胞数目和淀粉积累量降低,细胞充实度下降,粒重显著降低,且S3对其影响最大,S1次之,S2影响相对较小。郑单958和登海605两个品种S1、S2和S3成熟期的胚乳细胞数目较CK分别降低33%、6%、29%和41%、5%、29%,DH605 L处理显著提高了胚乳细胞增殖速率、胚乳细胞数目及淀粉含量,细胞充实度和粒重显著上升。遮阴导致籽粒灌浆速率减缓,灌浆高峰期推迟,2个品种S1、S2和S3的最大灌浆速率较CK分别降低34%、13%、58%和38%、13%、64%,登海605L处理提高了籽粒灌浆速率,籽粒灌浆高峰期提前出现。2个品种S1、S2和S3较CK分别减产58%、26%、81%和67%、27%、81%,登海605 L处理增产9%。即遮阴降低了籽粒胚乳细胞数目、淀粉含量和灌浆速率,进而影响产量,花粒期充足的光照则有助于籽粒胚乳细胞增殖和产量提高。

Response of Endosperm Cell Proliferation and Grain Yield of Summer Maize to Different Light Conditions

During the period from 2012 to 2014, Zhengdan 958 (ZD958) and Denghai 605 (DH605) were used with five treatments in a randomized complete block design with three replicates, including increasing light (L) from tassel stage (VT) to maturity stage (R6) and three shading treatments (40% of ambient light intensity) from VT to R6 (S1), from the sixth leaf stage (V6) to VT (S2), and from emergence stage (VE) to R6 (S3), and natural lighting in the field (CK). The illumination intensity of L on cloudy day was 1600?1800 μmol m^-2 s^-1. This experiment was conducted to explore the effects of light on endosperm cell proliferation, grain filling, starch content, dry matter accumulation and yield of summer maize. The dry matter accumulation of embryo and endosperm was significantly decreased under shading, as well as the content of starch and the endosperm cell plumpness decreased also. Effect of S3 on endosperm cell proliferation was the most, while that of S2 was the smallest. At R6, the endosperm cells number of S3, S2, S1 decreased by 33%, 6%, 29% in ZD958 and 41%, 5%, 29% in DH605. The dry matter accumulation of embryo and endosperm as well as the content of starch and the endosperm cell plumpness were increased after increasing light. The grain filling rate decreased and the days to maximum grain filling rate postponed under shading, while those increased after increasing light. The maximum grain filling rate of S1, S2, S3 decreased by 34%, 13%, 58% in ZD958 and 38%, 13%, 64% in DH605. The grain yield of S1, S2, S3 decreased by 58%, 26%, 81% in ZD958 and 67%, 27%, 81% in DH605. Results indicate that the number of endosperm cells, starch content and grain filling rate are decreased under shading, resulting in grain yield reducing, while L treatment can contribute to increasing the number of endosperm cell and grain yield.