土壤水分含量对银杏光合特性的影响

The Effects of Soil Water Contents on Photosynthetic Characteristics of Ginkgo

应用温室盆栽试验方法,采用完全随机试验设计,研究了4个家系1年生银杏实生苗在不同土壤水分条件下的光合特性。试验共设16处理,即4种水分水平(田间持水量的80%,60%,40%和20%)、4个银杏家系,处理为100d。结果表明:(1)在前两种土壤水分条件下,银杏净光合速率、气孔导度、细胞间隙CO2浓度、蒸腾速率及Fv/Fm差异较少,而在后两种土壤水分条件下,5个指标明显降低;(2)测定的各项指标之间相关系数都较大,其中与Fv/Fm相关密切的为净光合速率,与净光合速率相关密切的为细胞间隙CO2浓度和蒸腾速率;(3)土壤水分供应不足(即干旱胁迫)的条件下,银杏净光合速率随着土壤水分含量的下降而下降,主要因气孔限制所致,同时直接影响了光合作用的电子传递和CO2同化过程。

One year old seedlings of Ginkgo (Ginkgo biloba L.) were grown in a pot under greenhouse conditions with varying soil water levels to determine photosynthetic characteristics. There were 16 different treatments, including 4 water levels (80%, 60%, 40% and 20% of field capacity) and 4 varieties of Ginkgo, and the time of treatment was 100 days. The results were as follows: (1) There was little variation in the net photosynthetic rate, stomatal conductance,intercellular CO_2 concentration, transpiration rate and Fv/Fm at the water condition of 80% and 60% of field capacity, but the 5 indexes decreased obviously at the water condition of 40% and 20% of field capacity; (2) The correlation coefficients between 5 indexes were all high, and the correlation coefficients between net photosynthetic rate and intercellular CO_2 concentration was 0.951, and the correlation coefficients between Fv/Fm and net photosynthetic rate was 0.912; (3)The decreasing of net photosynthetic rate of Ginkgo under water stress was caused by stomatal limitation, and the electronic transmitting and CO_2 assimilating also were restrained under water stress.