不同气温与土壤湿度条件下籽蒿幼苗的表型可塑性

  植物表型可塑性是其适应环境的结果。为了探讨构件水平和全株水平表型可塑性的差异,我们选择籽蒿进行了双因素(气温:35 ℃、30 ℃、20 ℃; 土壤水分:对照、轻度、中度、重度胁迫)随机化区组实验以分析不同环境条件下植物的表型可塑性。结果表明,气温对籽蒿株高生长率有显著影响,土壤水分胁迫对籽蒿株高生长率无显著影响; 气温和土壤水分胁迫对籽蒿地上部生物量和根重生长率均无显著影响; 土壤水分胁迫对籽蒿幼苗根冠比有显著影响,而气温对其则无显著影响。这说明气温和土壤水分胁迫对籽蒿幼苗构件表型可塑性和全株表型可塑性的影响是有差异的。进一步分析表明,气温对籽蒿幼苗的叶含水量有显著影响,而对籽蒿幼苗的叶饱和亏无显著影响,这说明气温对籽蒿幼苗株高生长率的影响是通过影响其叶含水量来实现。

Phenotypic Plasticity of Artemisia sphaerocephala under Different Air Temperature and Soil Moisture

Plant phenotypic plasticity is its adaptation to environment. To discuss the divergence of the phenotypic plasticity in module level and whole plant level, taking Artemisia sphaerocephala as experimental plant, we performed a two-factor (air temperature: 35 ℃, 30 ℃, 20 ℃; and soil water stress: control, light, medium, heavy) randomized block design to analyze its phenotypic plasticity. The results showed that air temperature had significant influence on plant height of A. sphaerocephala seedlings, and soil water stress did not. Neither air temperature nor soil water stress had significant influences on the aboveground biomass and root biomass. Soil water stress had significant influence on root/shoot ratios of A. sphaerocephala seedlings, and air temperature did not. All these results suggested that there existed obvious differences on the influences of air temperature and soil water stress on the phenotypic plasticity of A. sphaerocephala seedlings in module level and whole plant level. Further analysis showed that air temperature had significant influence on leaf water content of A. sphaerocephala seedlings, but did not on leaf saturation deficit. Thus, the influence of air temperature on plant height of A. sphaerocephala seedlings might be realized by affecting its leaf water content.