旱稻水分利用率与碳同位素识别值之间的关系

通过温室盆栽试验 ,分析和探讨了三个水平的土壤水分条件对分蘖期和成熟期收获的旱稻(OryzasativaL .)生物量累积、水分利用率 (WUE)、植株不同部位的碳同位素识别值 (CID)的影响 ,并了解了它们之间的相互关系。水分条件包括 :饱和含水量 (W1 )、饱和含水量的 70 %(W2 )、饱和含水量的 4 0 %(W3)。结果表明当土壤水分条件从W1降低到W2时 ,分蘖期收获的生物量降低 4 5 %左右 ,成熟期收获的生物量降低 1 6 %～ 1 9%;而当从W1降低到W3时 ,分蘖期收获的生物量降低 73%左右 ,成熟期收获的生物量降低 5 5 %～ 5 7%。然而 ,根据地上部干重计算而来的WUE(WUE 地上部 )和根据全株干重计算而来的WUE(WUE 全株 )则随土壤含水量的降低而增加 ,其增幅在分蘖期为 0 .0 7～ 0 .2 8gkg-1 ,在成熟期为 0 .0 7～ 0 .4 5gkg-1 。植株的CID值变幅为 1 7.0～ 2 0 .6 ,但植株不同部位间差别显著 ,分蘖期收获的样品CID值从小到大的顺序为 :根 <最近完全伸展叶 <叶芽 <茎秆 ;而成熟期收获的样品CID值从小到大的顺序为 :籽粒 <根 <茎秆 <旗叶。随着土壤含水量的降低 ,植株所有部位的CID值亦显著减小。叶部的CID值与WUE 地上部(和WUE 全株 )之间呈一致的负相关关系。

WATER-USE EFFICIENCY OF UPLAND RICE AND CARBON ISOTOPE DISCRIMINATION

A pot experiment was conducted in a glasshouse to clarify and quantify the effect of soil water regimes on dry matter production,water-use efficiency (WUE),and carbon isotope discrimination (CID) of different plant parts of upland rice (Oryza sativa L.) measured at the tillering and maturing stages,and to understand the relationship between WUE and CID.Three water regimes were imposed: saturated condition (W1),70% of saturation moisture (W2),40% of saturation moisture (W3).Results of the experiment showed that biomass accumulation decreased by 45% at the tillering stage,and by 16%~19% at the maturing stage with soil water regime changing from W1 to W2,and by 73% and by 55%~57% with soil water regime from W1 to W3.On the other hand,above ground dry matter-based WUE (WUE_A) and total dry matter based WUE (WUE_T) increased with rising water stress by 0.07~0.28 g kg^-1 at the tillering stage,and by 0.07~0.45 g kg^-1 at the ma turing stage.The values of CID of the plant varied from 17.0 to 20.6 with significant differences among plant parts,which can be lined in an order of rootCID values of all the analyzed plant parts significantly decreased with rising water stress.A consistent negative relationship between the CID values of leaves and WUE_A(and WUE_T) was ob served.