土壤干旱胁迫对黄栌叶片光合作用的影响

采用CIRAS-2型便携式光合作用系统,设置充足供水、轻度、中度和重度胁迫4种土壤水分处理,研究土壤干旱和强光胁迫对3年生黄栌苗木叶片光合作用的影响.结果表明:土壤干旱胁迫对黄栌叶片的光合性能参数影响显著,随着土壤水分胁迫的加剧,黄栌叶片的光合速率、蒸腾速率和光量子效率明显降低,光补偿点增高,水分利用效率在轻度水分胁迫(土壤相对含水量60%～65%)下最高;在强光(有效辐射强度1000～1800μmol.m-2.s-1)范围内,叶片光合速率和水分利用效率均较高,而对弱光的光能吸收和光量子效率较低,并随土壤水分胁迫加剧明显下降.

Responses of Cotinus coggygria var. cinerea photosynthesis to soil drought stress

By using a portable photosynthetic system (CIRAS-2), this paper studied the photosynthetic characters of 3-year-old Cotinus coggygria var. cinerea under effects of different soil water regime (enough supply, light stress, medium stress, and heavy stress) and light intensity. Soil water regime had significant effects on the photosynthetic parameters of C. coggygria. With increasing drought stress, the net photosynthetic rate, transpiration rate, and apparent yield all declined apparently, while the light compensation point increased. The highest water use efficiency was found under light water stress (soil relative water content being about 60% -65%). C. coggygria had higher net photosynthetic rate and higher water use efficiency under a wide range of high light intensity (photosynthetically active radiation being 1000-1800 micromol x m(-2) x s(-1)), but had lower efficiency of light absorbance and conversion, i.e., lower apparent quantum yield, under low light intensity, which was declined more significantly when the soil water stress was intensified.