2个地被菊品种对不同遮光处理的生理适应性

Physiological characteristics of adaptability for two ground-cover chrysanthemum cultivars with shading

为探究地被菊Chrysanthemum grandiflorum在不同遮光处理下的生理适应性,以地被菊‘梅红’‘Meihong’‘金不换’‘Jinbuhuan’为试验材料,通过人工搭设不同透光率(A:25%透光率;B:50%透光率;C:85%透光率;ck:全光照)的遮阳网对它们进行遮光逆境胁迫处理。结果表明:随着遮光程度的增加,地被菊株高、叶面积、节间长度、叶绿素质量分数和花径等呈增加趋势,冠幅、基径、比叶质量、叶绿素a/b值、分枝数和成花量等呈降低趋势;地被菊在遮光条件下的光饱和点、光补偿点及暗呼吸速率下降,表现出它们在弱光条件下的生理适应机制;地被菊虽是阳生植物,但其光照生态幅较宽,轻度遮光(85%透光率)能促进其光合效率,减少光抑制,促进长势,当透光率达减少到25%时,仍能正常开花;另外,不同品种对光的适应能力存在一定的差异性,‘金不换’对光强的生态适应范围大于‘梅红’。

To determine the physiological adaption of two shade-tolerant, ground-cover Chrysanthemum grandi- florum cultivars, a greenhouse experiment was conducted with four shading treatments （transmittance of 25%, 50%, 85%, and 100% ） with C. grandiflorum ＇Jinbuhuan＇ and C. grandiflorum ＇Meihong＇. Light response curve for each plant were measured by LI-6400. For each treatment, three leaves （i.e. three replicates） were selected and alternatively. Results showed that with increased shading, the plant height, leaf area, flower diam- eter, internode length, and total chlorophyll content （chlorophyll a ＋ b） of the C. grandiflorum cuhivars in- creased significantly （P〈0.05）; whereas, crown width, stem diameter, specific leaf weight （SLW）, ratio of chlorophyll a to chlorophyll b （chlorophyll a/b）, number of flowers, and number of branches decreased （P〈 0.05）. Photosynthetic light compensation point （LCP）, photosynthetic light saturation point （LSP）, and dark respiration rate （Rd） also decreased （P〈0.05）as physiological adaptability to light decreased. Moderate shad- ing （85% transmittance） improved photosynthetic capacity and reduced photo inhibition; even with 25% transmittance, normal flowering occurred. However, physiological adaption of cultivars varied according to the range of ecological adaptation to light intensity with C. grandiflorum ＇Jinbuhuan＇ being broader than C. grandiflo- rum ＇Meihong＇. [Ch, 2 fig. 6 tab. 24 ref.]