3种野牡丹属植物的光合特性

Photosynthetic characteristics of 3 Melastoma L. species

为探索野牡丹属的光合特性差异,促进本土野牡丹属植物在城市园林中的推广应用,以3种野牡丹属植物(野牡丹、毛稔、紫毛野牡丹)为试验材料,研究其光响应曲线及参数、CO2响应曲线及参数、叶绿素含量等光合特性差异。结果表明:三者的光补偿点(LCP)分别为15.222、23.167和24.271μmol·m-2·s-1,光饱和点(LSP)分别为603.593、760.222和783.632μmol·m-2·s-1,为阳生植物;野牡丹的最大净光合速率(Pnmax)最高,为6.620μmol·m-2·s-1,冬季低温会导致其出现光抑制现象;毛稔和紫毛野牡丹CO2饱和阶段的Pnmax高于光饱和阶段,表明毛稔和紫毛野牡丹在强光下的光合速率受CO2供应的限制。综合光补偿点(LCP)、表观量子利用效率(AQY)、叶绿素含量及叶绿素a/b等指标,耐阴性由强到弱为野牡丹>毛稔>紫毛野牡丹。野牡丹、毛稔、紫毛野牡丹适宜在阳光充足环境下种植,例如向阳的山坡、林缘、路边;野牡丹还可种植在枝叶较为稀疏的乔木下层;此外,野牡丹对冬季自然低温敏感性较强,在南方冬季温度较低的地区应对其进行适当的防寒处理。

To provide references for the application of local plants of Melastoma L.,M.candidum,M.sanguineum and M.penicillatum were studied in terms of the differences in their photosynthetic characteristics such as the light response and parameters,CO2 response curves and parameters and chlorophyll content.The results showed that the light compensation point(LCP)of the 3 species of Melastoma L.were 15.222,23.167 and 24.271μmol·m-2·s-1.And light saturation point(LSP)were 603.593,760.222 and 783.632μmol·m-2·s-1.Thus they are all the sun plants.The maximum net photosynthetic rate(Pnmax)of M.candidum was 6.620μmol·m-2·s-1,which was highest among those of the 3 species.However,the photoinhibiton in M.candidum was induced by the low temperature in winter.The Pnmax of M.sanguineum and M.penicillatum under conditions of saturated CO2 concentrations were higher than their Pnmax under conditions of saturated photosynthetically activeradiation intensities,which demonstated the net photosynthetic rates of the two species were limited by available CO2.Taking light compensation point(LCP),apparent quantum yield(AQY),chlorophyll content(Chl a+b)and chlorophyll a/b(Chl a/b)into consideration together,our experiment showed that their shade-tolerance from high to low was in the order of M.candidum,M.sanguineum and M.penicillatum.In conclusion,the 3 species of Melastoma L.are suitable for sunny places such as sunny slope,forest edge and roadside.M.candidum also grows well in the layer under tree with a bit sparse branches and leaves.In addition,M.candidum is sensitive to the low temperature in winter,so some measures resisting cold should be taken in the areas where it's a bit colder in winter.