不同CO2浓度和N肥水平对粳稻茎鞘非结构性碳水化合物含量与积累的影响

为了解CO2浓度升高和N肥水平对水稻茎鞘内非结构性碳水化合物(NSC)含量和积累量的影响,利用开顶式气室(OTC),以常规粳稻"南粳9108"为试验材料,设置3个CO2浓度水平:对照T0(背景大气)、T0+120μmol·mol-1(T1)和T0+200μmol·mol-1(T2)。在OTC内采用盆栽方式,设置3个氮(N)肥水平:10 g N·m^-2(N1)、20 g N·m^-2(N2)和30g N·m^-2(N3)。分别于水稻抽穗期、灌浆期(抽穗后20 d)和成熟期对地上部分各器官生物量、茎鞘NSC含量以及顶部四张叶片的N含量进行分析。结果表明:CO2浓度升高对抽穗期叶N含量总体无显著影响,但显著降低灌浆期N2和N3水平的叶N含量;CO2浓度升高对抽穗期茎鞘NSC含量和积累量无显著影响,抽穗期置换到高CO2浓度环境使灌浆期茎鞘NSC积累显著增加,置换到低CO2浓度环境使NSC积累显著减少。同一CO2浓度条件下,NSC含量和积累量均为N1>N2>N3,且N1处理均显著高于N3处理,CO2浓度升高和N水平的交互作用对灌浆期茎鞘NSC含量影响显著。水稻产量在不同CO2浓度水平间无显著差异,但随施氮水平的提高而增加。抽穗期与灌浆期水稻茎鞘NSC含量和积累量与茎鞘干重呈极显著正相关,与叶N含量呈极显著负相关;叶N衰减越慢,灌浆期水稻茎鞘NSC残留比(RNSC)越低;结实率和产量与RNSC呈显著负相关,RNSC越大,茎鞘NSC转移的越少,结实率和产量越低。

Effects of different CO2 concentrations and nitrogen application levels on content and accumulation of non-structural carbohydrate in stem sheath of Japonica rice

To investigate the effects of elevated CO2 concentrationCO2]and nitrogen fertilization on the content and accumulation of non-structural carbohydrate(NSC)in stem sheath of rice,a Japonica rice(Oryza sativa L.)‘Nanjing 9108’was grown in a OTC pot experiment with three CO2 concentrations:ambient(T0),ambient+120μmol·mol-1(T1),and amibent+200μmol·mol-1(T2)in open-top chambers(OTC),and three nitrogen(N)fertilization levels:10 g N·m^-2(N1),20 g N·m^-2(N2),and 30 g N·m^-2(N3).We measured aboveground biomass,NSC content in stem sheath and nitrogen content in the top four leaves at heading,filling(20 d after heading),and mature stage.Results showed that there was no significant effect of elevatedCO2]on N content in leaves at the heading stage,while it significantly reduced the Ncontent in leaves at N2 and N3 levels during the filling stage.ElevatedCO2]did not affect the content and accumulation of NSC in stem sheath at the heading stage.The accumulation of NSC in stem sheath significantly increased when the pots were transferred to higherCO2]at the heading stage,but significantly decreased when the pots were transferred to lowerCO2]at the heading stage.Under the sameCO2],both the content and accumulation of NSC were N1>N2>N3,being significantly higher under N1 than under N3.There was no significant difference in rice yield at differentCO2],but the yield increased with the increasing N fertilization levels.ElevatedCO2]and N fertilization levels significantly interacted to affect the content of NSC in stem sheath during the filling period.The content and accumulation of NSC in stem sheath at the heading and filling stages were positively correlated with dry weight of stem sheath and negatively correlated with N content in leaves.The slower N attenuation in leaves,the lower NSC residual ratio(RNSC)was.There was a significant negative correlation between seed setting rate,yield and RNSC at the filling stage,suggesting that there would be less NSC transferred out from stem sheath,lower seed setting rate and lower yield with higher RNSC.