摘要
利用稻田FACE(Free Air CO_2Enrichment)系统平台,以杂交稻汕优63为供试材料,二氧化碳设环境CO_2浓度(Ambient)和高CO_2浓度(Ambient+200μmol/mol),抽穗期源库改变设剪叶(剪除剑叶)和疏花处理(相间剪除1次枝梗),以不处理为对照(CK),研究大气CO_2浓度升高对不同源库处理水稻产量形成及物质生产的影响。结果表明:CK条件下,大气CO_2浓度升高使汕优63籽粒产量显著增加32%,这主要与单位面积总颖花量大幅增加(+26%)有关,结实能力亦呈增加趋势但未达显著水平。大气CO_2浓度升高使抽穗期剪叶处理水稻的籽粒产量平均增加55%,明显大于对照水稻,这主要与受精率(+28%)、饱粒率(+23%)和所有籽粒平均粒重(+19%)大幅增加有关。相反,对抽穗期疏花处理水稻而言,高CO_2浓度环境下籽粒产量的增幅(+25%,P=0.07)明显小于对照水稻,这主要与结实能力的响应略有下调有关。与产量响应类似,大气CO_2浓度升高使对照、剪叶和疏花条件下最终生物量分别增加39%、43%和28%,除疏花处理外均达显著水平。抽穗期剪叶和疏花处理本身使水稻籽粒产量分别降低40%和45%,前者主要是结实能力大幅下降所致,而后者与总颖花量减半相关。以上结果表明,大气CO_2浓度升高使杂交水稻生产力大幅增加,人为减小源库比(如剪叶)可增强CO_2肥料效应,而增加源库比(如疏花)则可使这种肥料效应减弱。
Empirical records have proven global climate change to be an indisputable fact, with an important contribution from the increase in atmospheric carbon dioxide （ CO2） concentration. According to the projections of the Intergovernmental Panel on Climate Change （IPCC） in 2007, global CO2 concentration is expected to double in the middle of the 21st century compared to its pre-industrial level. As the main substrate for plant photosynthesis, elevated CO2 concentration will directly influence the growth and development of all terrestrial higher plants, especially those grown as crops. Rice （ Oryza sativa L.） is one of the most important crops in the world and is the primary staple food in Asia, as well as China. Many studies have indicated that increasing CO2 concentration generally increases the grain yield of rice, but it is unclear whether this CO2 fertilization effect varies with alteration in the source-sink relationship of plants. In order to answer this question, we designed an experiment with treatments of elevated CO2 concentration and source-sink manipulation of the hybrid rice Shanyou 63 by using a rice Free Air CO2 Enrichment （FACE） facility at Jiangdu （119°42＇0＂E, 32°35＇5＂N）, Yangzhou, China, in 2011. Rice plants were grown under two levels of CO2 concentration （ambient and ambient ＋ 200 μmol/mol） from transplanting until maturity. Source-sink manipulation was achieved through cutting off the whole flag leaf （ LC, leaf cutting） or half of the spikelets at heading （SC, spikelets cutting; remove every other primary branch of a panicle）. The results showed that under the CK （control, no leaf or spikelet cutting） condition, elevated CO2 concentration increased grain yield by 32% （P〈0.05） , which was mainly due to the increase in spikelet number per square meter （＋26%, P〈 0.05） and was partly due to the non-significant increase in fertility. On average, CO2 elevation increased grain yield by 55% （P〈0.01） for LC-crops, with the increase being much larger than that of CK-crops. This higher response was mainly attributed to the dramatic increase in fertile grain percentage （＋28%, P〈0.05） , filled grain percentage （ ＋23%, P〈 0.05）, and average grain weight （ ＋19%, P〈0.05）. By contrast, for SC-crops, the yield response to the high COz level （ ＋ 25%, P= 0.07） was much lower than that of CK-crops, which was related to the trends of down-regulation in fertility. Similarly, elevated CO2 concentration increased the final aboveground biomass by 39%, 43%, and 28%, for CK-, LC-, and SC-crops, respectively, with the effect being significant for the former two. Compared with CK, LC- and SC-treatment at heading significantly decreased grain yield by 40% and 45%, respectively. The former was mainly due to the great decrease in grain fertility, while the latter was linked with the reduction in total spikelet number by half. Compared to CK, LC-treatment at heading significantly decreased the leaf, stem and sheath, panicle, and above-ground biomass at maturity by 29% （P〈0.05）, 32% （P〈0.01）, 28% （P〈0.01）, and 29% （P〈0.01）, respectively; SC-treatment reduced the biomass of the corresponding plant parts by 15% （P= 0.24）, 33% （P〈0.05）, 47% （P〈0.01）, and 17% （P〈O.05）, respectively. These results indicated that elevated atmospheric CO2 concentration greatly increased the productivity of hybrid rice. Furthermore, this fertilization effect was enhanced by decreasing the source-sink ratio （ i.e., leaf cutting at heading）, but was reduced by increasing the source-sink ratio （ i.e., spikelet cutting at heading）.
出处
《生态学报》
CAS
CSCD
北大核心
2016年第15期4751-4761,共11页
Acta Ecologica Sinica
基金
国家自然科学基金面上项目(31371563,31171460,31071359,31571597)
国家自然科学基金国际(地区)合作与交流项目(31261140364)
江苏省高校自然科学重大基础研究项目(11KJA210003)
科技部国际合作计划项目(2010DFA22770)
江苏高校优势学科建设工程资助项目
作者简介
通讯作者Correspondingauthor．E—mail：lxyang@yzu．edu．cn
