You C.,Nanjing Agricultural University |
You C.,Key Laboratory of Crop Physiology Ecology and Production Management |
Zhu H.,Nanjing Agricultural University |
Zhu H.,Key Laboratory of Crop Physiology Ecology and Production Management |
And 20 more authors.
Frontiers in Plant Science | Year: 2016
Large-panicle rice cultivars often fail to reach their yield potential due to the poor grain filling of inferior spikelets (IS). Thus, it is important to determine the causes of poor IS grain filling. In this study, we attempted to identify whether inferior grain filling of large panicles is restricted by superior spikelets (SS) and their physiological mechanism. SS were removed from two homozygous japonica rice strains (W1844 and WJ165) during flowering in an attempt to force photosynthate transport to the IS. We measured the effects of SS removal on seed setting rate, grain weight, grain filling rate, sucrose content, as well as hormone levels, activities of key enzymes, and expression of genes involved in sucrose to starch metabolism in rice IS during grain filling. The results showed that SS removal improved IS grain filling by increasing the seed setting rate, grain weight, sucrose content, and hormone levels. SS removal also enhanced the activities of key enzymes and the expression levels of genes involved in sucrose to starch metabolism. These results suggest that sucrose and several hormones act as signal substances and play a vital role in grain filling by regulating enzyme activities and gene expression. Therefore, IS grain filling is restricted by SS, which limit assimilate supply and plant hormones, leading to poor grain filling of IS. © 2016 You, Zhu, Xu, Huang, Wang, Ding, Liu, Li, Chen, Ding and Tang.
Hou P.,Nanjing Agricultural University |
Hou P.,Key Laboratory of Crop Physiology Ecology and Production Management |
Li G.,Nanjing Agricultural University |
Li G.,Key Laboratory of Crop Physiology Ecology and Production Management |
And 13 more authors.
Journal of Environmental Sciences (China) | Year: 2013
A three-year experiment was conducted in the middle-lower reaches of the Yangtze River in China to study the influence of continuous wheat straw return during the rice season and continuous rice straw return in wheat on methane (CH4) emissions from rice fields in which, the rice-wheat rotation system is the most dominant planting pattern. The field experiment was initiated in October 2009 and has continued since the wheat-growing season of that year. The analyses for the present study were conducted in the second (2011) and third (2012) rice growing seasons. Four treatments, namely, the continuous return of wheat straw and rice straw in every season (WR), of rice straw but no wheat straw return (R), of wheat straw but no rice straw return (W) and a control with no straw return (CK), were laid out in a randomized split-plot design. The total seasonal CH4 emissions ranged from 107.4 to 491.7 kg/ha (2011) and 160.3 to 909.6 kg/ha (2012). The increase in CH4 emissions for treatments WR and W were 289% and 230% in the second year and 185% and 225% in the third year, respectively, in relation to CK. We observed less methane emissions in the treatment R than in CK by 14%-43%, but not statistically significant. Treatment R could increase rice productivity while no more CH4 emission occurs. The difference in the total CH4 emissions mainly related to a difference in the methane flux rate during the first 30-35 days after transplant in the rice growing season, which was caused by the amount of dissolved oxygen in paddy water and the amount of reducible soil materials. © 2013 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences.