温度和CO_(2)浓度升高下双季稻茎蘖动态、成穗率与产量的关系

Relationships between Tiller Dynamic,Earbearing Tiller Rate and Yield of Double Cropping Rice under Elevated Temperature and CO_(2)Concentration

为明确气候变化下我国双季稻茎蘖动态与成穗特征的变化及其与产量的关系,利用开顶式气室(OTC)连续开展4年8个生长季的大田气候变化原位模拟试验,设置对照(CK)、增温2℃(ET)、CO_(2)浓度增加60μmol/mol(EC)、同时增温增CO_(2)浓度(ETEC)共4个处理,研究双季稻生育期内茎蘖动态、成穗率变化特征以及对产量的影响。结果表明,随着累积辐射量和生长度日(GDD)升高,水稻分蘖达到峰值后部分消亡,且早稻分蘖增长和消亡速率均大于晚稻。相比CK,ET、EC和ETEC条件下早稻最大分蘖数和无效分蘖数分别提高3.6%~14.2%和8.9%~134.2%,成穗率降低0.4%~9.3%,对产量形成具有不利影响;晚稻最大分蘖数提高2.9%~13.1%,无效分蘖数降低1.6%~64.8%,成穗率提高1.7%~22.1%,有助于产量增长。ETEC处理对双季稻最大分蘖具有正向协同的交互作用,而对无效分蘖和成穗率的交互作用不显著。总体而言,大气温度和CO_(2)浓度升高对早稻分蘖和成穗具有负效应,对晚稻表现为正效应,未来气候变化背景下提高水稻茎蘖数,控制无效分蘖,进而提高成穗率,对水稻稳产增产具有重要意义。

In order to clarify the variation of tiller dynamic and earbearing tiller rate of Chinese double cropping rice under climate change and their relationship with yield formation,a field experiment was conducted using open-top chambers(OTC)to simulate different scenarios of elevated temperature and/or CO_(2)concentration for four rotations of double rice.There were four treatments,CK,ET(OTC with 2℃temperature elevation),EC(OTC with 60μmol/mol CO_(2)elevation),ETEC(OTC with simultaneous 2℃temperature and 60μmol/mol CO_(2)elevation).The characteristics of tiller dynamic,earbearing tiller rate and their effect on rice yield were explored.The results showed that rice tiller reached the peak then partially declined with the increase of cumulative radiation and growth degree-day(GDD),and the tiller growth/extinction rate in early rice was higher than that in late rice.Compared with CK,ET,EC and ETEC treatments in early rice increased number of maximum tiller and invalid tiller by 3.6%-14.2%and 8.9%-134.2%,respectively,and decreased earbearing tiller rate by 0.4%-9.3%,which had negative effect on yield formation.In late rice,ET,EC and ETEC treatments increased maximum tiller number and ear bearing tiller rate by 2.9%-13.1%and 1.7%-22.1%,respectively,and decreased ineffective tiller number by 1.6%-64.8%,which contributed to the increase in yield.ETEC treatment showed a positive synergy on the promotion of maximum tiller,while their interaction on ineffective tiller number and earbearing tiller rate was not significant.Generally,elevated temperature and CO_(2)concentration had a negative effect on tillering and earbearing for early rice,while had a positive effect for late rice.Under the background of future climate change,it was of great significance to promote rice tiller development,control ineffective tiller and increase earbearing tiller rate for stable and high yield output.