摘要
[Objective] Through the discussion of diurnal changes of photosynthesis of Flaveria bidentis at the seedling stage under different soil moisture conditions,photosynthetic physiological basis of Flaveria bidentis to adjust to drought stress is investigated in order to provide a theoretical basis for prevention of further invasion. [Method] The seeds of Flaveria bidentis were planted in plastic buckets laid within all-transparent canopy. It was set with 3 soil moisture treatments,that is,the soil relative water contents （SRWC） were 80% （CK）,60% （T1）,30% （T2） of field maximum moisture capacity. Photosynthetic parameters and diurnal changes of relevant ecological factors of Flaveria bidentis at the seedling stage were measured and the differences between different treatments were compared. [Result] Under CK treatment,the diurnal changing curve of Pn of Flaveria bidentis was basically in a ＂bimodal＂ shape,while under T1 and T2 treatment,Pn was a ＂unimodal＂ curve. At about 11：30 am,CK reaches its first peak value of 31.83 μmol/（m2·s） and its second peak value of 23.34 μmol/（m2·s） appears at 15：30. At 13：30 T1 and T2 have their peak values. The diurnal changes of Tr of Flaveria bidentis leaves in the three treatments are all in a unimodal curve. There are no significant differences between CK and T2 treatments,while the diurnal water use efficiency in T1 treatment is obviously below the ones in CK and T2 treatments. [Conclusion] Drought stress reduces Pn,Tr,Sc and other physiological indices of Flaveria bidentis. The reason why Pn is reduced is due to both stoma and non-stoma factors. Drought stress also postpones the appearance of Pn peak value. Proper drought can efficiently promote water use efficiency of Flaveria bidentis and cause its anti-drought reaction.
[目的]探讨不同土壤水分条件下黄顶菊苗期光合特性的日变化规律,探究黄顶菊适应干旱胁迫的光合生理基础,为进一步预防其入侵提供理论依据。[方法]将黄顶菊种植在塑料桶中,并放于全透光的遮雨棚内,设3种土壤水分处理,即土壤相对含水量分别为田间最大持水量的80%(CK)、60%(T1)、30%(T2),对苗期黄顶菊的光合参数及相关生态因子的日变化进行测定,并比较不同处理间的差异。[结果]在CK条件下,黄顶菊的Pn日变化曲线基本呈"双峰"型,但在T1和T2处理条件下Pn呈"单峰"曲线;CK在上午11:30左右达到第1个峰值,为31.83μmol/(m2.s),13:30午休,下午15:30再次达到峰值,为23.34μmol/(m2.s)。而T1、T2在13:30达到峰值;3个处理黄顶菊叶片的Tr日变化均呈"单峰"曲线;CK与T2处理间无显著差异,而T1处理的日平均水分利用效率显著低于CK和T2处理。[结论]干旱胁迫降低了黄顶菊叶片的Pn、Tr、Sc等生理指标;净光合速率下降的原因既有气孔因素又有非气孔限制因素;干旱胁迫推迟了净光合效率峰值出现的时间;适度干旱能够有效提高黄顶菊的水分利用效率引起其抗旱性响应。
基金
Supported by Research upon Prevention and Control of New Invasive PlantFlaveria bidentis(200803022)~~
