水分胁迫对扶芳藤生长及光合特性的影响

以盆栽2 a生扶芳藤扦插苗为试材,研究了4种土壤相对含水量(20%、40%、60%、80%)条件下枝条的生长及生理特性。结果表明:随着土壤相对含水量的增高,枝条及叶片生长生长量、叶片质量、叶片净光合速率增强。净光合速率的日变化呈双峰曲线,有“午休”现象。土壤相对含水量为60%和80%时,其枝条、叶片生长量较大,叶片净光合速率较强,第1次高峰出现在11:00,第2次高峰出现在15:00。随着土壤相对含水量的降低,枝条生长量、叶片质量、叶片净光合速率降低。土壤相对含水量在20%和40%时,净光合速率第1次高峰提前,均出现在9:00,峰值较低;第2次高峰分别出现在13:00和15:00。土壤相对含水量在20%时,枝条、叶片仍能缓慢生长,表现出较强的抗旱性。

Effects of Water Stress on the Growth and Photosynthesis Characters of Euonymus fortunei

2-year-old potted grown plants raised by the cuttings of Euonymus fortunei were used as materials to study the growth of branches and physiological soil characters under conditions of four artificial controlled drought gradient(20%,40%,60% and 80%).The results showed that branch growing quantity,leaf weight and leaf net photosynthesis rate increased with the raise of soil relative water content.Midday depression of photosynthesis existed.When soil relative water content(SRWC) was above 60%,branch and leaf growing quantity were larger,net photosynthesis rate was better.The curve of diurnal variation of leaf net photosynthesis showed two peaks,the first peak appeared at 11:00 and the second one appeared at 15:00.Branch growing quantity,leaf weight and leaf net photosynthesis rate dropped with the decrease of SRWC.When SRWC were 20% and 40%,the first peak of diurnal variation of the leaf net photosynthesis appeared at 9:00,the peak was lower;the second peak appeared at 13:00 and 15:00.When SRWC was 20%,branches and leaves grew slowly,indicating that E.fortunei had strong drought resistant capability.