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在控制试验条件下通过盆栽试验设置3个土壤水分[分别为田间持水量(FC)的80%、50%和30%]处理,研究土壤水分状况对麻疯树幼苗光合作用、超微结构及生理特征的影响.结果表明:土壤含水量为80%FC时,麻疯树叶片净光合速率(Pn)、光合色素含量、稳定碳同位素比率(δ~(13)C)、N含量和水分利用效率(WUE)最低;丙二醛(MDA)和过氧化氢(H_2O_2)含量、气孔导度(gs)、胞间CO_2浓度(Ci)和蒸腾速率(Tr)最高;叶肉细胞超微结构显示,叶绿体内部形成较大的淀粉粒,挤压严重.土壤含水量为50%FC时,MDA和H_2O_2含量、gs、Ci和Tr显著地高于30%FC处理,而叶片N含量和δ~(13)C与30%FC处理无显著差异.土壤含水量为30%FC时,Pn、光合色素含量、叶片N含量和WUE最大,MDA和H_2O_2含量最低;叶绿体内部淀粉粒和嗜饿颗粒体积较小,内部结构清晰可见,叶绿体膜结构完整.考虑到麻疯树是主要以种子为经济价值的树种,结合四川攀西地区的土壤养分状况,土壤湿度应控制在田间持水量的30%～50%左右,此时麻疯树光合作用最强,叶片N含量最高,WUE最大,将更有利于其生长结实,而过多的土壤水分可能会导致其徒长.图4表1参28
Three soil moisture treatments (80%, 50% and 30%, respectively) were set up under pot experiment to control the effects of soil moisture on the photosynthesis, ultrastructure, The results showed that the net photosynthetic rate (Pn), photosynthetic pigment content, stable carbon isotope ratio (δ ~ (13) C), N content and water use of Jatropha curcas leaves at the soil moisture content of 80% (WUE) was the lowest; the content of malondialdehyde (MDA) and hydrogen peroxide (H 2 O 2), stomatal conductance (Gs), intercellular CO 2 concentration (Ci) and transpiration rate (Tr) In the chloroplast, larger starch grains were formed and were severely squeezed. The content of MDA and H_2O_2, gs, Ci and Tr were significantly higher than those of 30% FC when the soil water content was 50% FC, while the leaf N content and δ ~ 13 ) C had no significant difference with that of 30% FC treatment.When the soil water content was 30% FC, Pn, photosynthetic pigment content, leaf N content and WUE were the highest and MDA and H_2O_2 contents were the lowest. The volume of starch granules and starvation granules in chloroplast was small , The internal structure is clearly visible, the chloroplast membrane structure is complete.According to the Jatropha curcas is a seed mainly for economic value of species, combined Soil nutrient status and soil moisture in Panxi of Sichuan Province should be controlled at about 30% ~ 50% of the field capacity. At this time, Jatropha curcas photosynthesis strongest, leaves N content highest, WUE maximum, will be more conducive to its growth and fruiting , While excessive soil moisture may cause it to become leggy