遮阴对多花黄精生长及光合特性的影响

Response of growth and photosynthetic characteristics of Polygonatum cyrtonema to shading conditions

该研究以盆栽的多花黄精为材料,以透光率为100%为对照(CK),通过梯度遮光处理(80%,60%,35%),比较研究不同遮阴程度对多花黄精的生长、光合荧光特性及物质分配的影响,以期为多花黄精栽培模式的选择和栽培措施的改进提供理论指导。结果表明,总体而言,遮阴显著降低了多花黄精叶片细胞中O-·2产生速率、H2O2含量、MDA含量和相对电导率,并使SOD,POD,CAT酶活性维持在较高水平。同时,遮阴还促进了多花黄精叶片叶绿素a、叶绿素b和总叶绿素的合成;提高了净光合速率(Pn)、气孔导度(Gs)和蒸腾速率(Tr);降低了胞间CO2浓度(Ci);并有效缓解了Fv/Fm,ΦPSⅡ,q P下降和Fo,NPQ上升的趋势,使多花黄精光合作用效率和PSⅡ光学活性维持在较高水平。遮阴有利于多花黄精生长,能显著提高多花黄精总生物量,但过度遮阴会促进光合产物向地上部分运输,从而会降低光合产物向根茎的分配比例,使多花黄精根茎产量和黄精多糖(活性成分)含量下降。就该试验而言,60%的透光环境适宜多花黄精的生长,并有利于多花黄精根茎产量和品质的形成。

The purpose of this experiment was to study the effects of different shading conditions on the growth,physiological characteristics and biomass allocation of Polygonatum cyrtonema,which offered a theoretical basis for its cultivation.Different light environments(100%,80%,60% and 35% light transmittance) were simulated with shading treatments.Growth and photosynthetic indexes of P.cyrtonema were measured and the variances were analyzed.The results show that shading decreased superoxide anion radical(O-·2)production rate and hydrogen peroxide(H2O2) accumulation,kept the activity of SOD,POD and CAT enzyme at a high level.Furthermore,The content of chlorophyll a and chlorophyll b,net photosynthetic rate(Pn),stomatal conductance(Gs),transpiration rate(Tr),maximal photochemical efficiency of photosystem Ⅱ(Fv/Fm),photochemical quenching index(q P) and effective quantum yield of photosystem II(ΦPSⅡ) of P.cyrtonema were increased while the intercellular CO2 concentration(Ci),Foand NPQ were decreased by shading.Shading is beneficial to P.cyrtonema growth,can increase the total biomass P.cyrtonema.The allocation proportion of biomass on the aerial portion of P.cyrtonema increased but underground parts decreased with increasing shading conditions.In this study,P.cyrtonema can grow well in shading conditions,shading is beneficial to the formation of the yield and quality of the rhizomes of P.cyrtonema,especially in 65% light transmittance.