不同叶型丹参光合特性研究

为了研究大叶型丹参和小叶型丹参(栽培变种)光合特性,为其合理栽培提供依据,使用LI-6400XT便携式光合仪测定了2种叶型丹参光合速率对光强的响应曲线及光合日变化情况。结果表明,大叶型丹参的光补偿点和光饱和点低于小叶型丹参;2种叶型丹参表观量子利用率均在0.06以上,对弱光利用率高;净光合日变化均为双峰型,光合峰值出现在11:30和14:30,13:00前后出现“午休”现象,大叶型丹参“午休”更为剧烈;大叶型丹参的“午休”属非气孔限制型,小叶型丹参的“午休”属气孔限制型;气孔导度和蒸腾速率日变化均呈单峰型。大叶型丹参午间蒸腾作用剧烈造成局部水分亏缺是其光合“午休”的重要因素,栽培中应考虑与适当高秆作物间作或套作,降低其蒸腾速率,缓解光合“午休”,提高产量。

A study on photosynthetic characteristics of different Salvia miltiorrhiza varieties

To provide basic data for planting S.miltiorrhiza cv.silcestris and S.miltiorrhiza cv.sativa,their photosynthetic characteristics were studied.A LI-6400XT portable photosynthesis system was used to measure diurnal dynamics of the photosynthetic characteristics and light-response curve of photosynthesis.The light compensation point and light saturation point of S.miltiorrhiza cv.sativa were lower than those of S.miltiorrhiza cv.silcestris.The apparent quantum efficiencies were higher than 0.06,which showed that they had a strong utilization efficiency in weak light.Diurnal course curves of their net photosynthetic rates had two peaks,one occurred at 11:30 and the other at 14:30.Their "midday depression" occurred at 13:00.The "midday depression" of S.miltiorrhiza cv.silcestris was due to stomatal limitation while that of S.miltiorrhiza cv.sativa was not.Diurnal course curves of their stomatal conductance and transpiration rate had a single peak.The "midday depression" of S.miltiorrhiza cv.sativa was deduced to be due to localized water stress in leaves when the transpiration rate was high at midday.To ease "midday depression" and increase production of S.miltiorrhiza cv.sativa,some tall crops should be intercropped.