遮阴对不同生长速率菜心生长及生理的影响

Effects of Shading on the Growth and Physiology of Flowering Chinese Cabbage at Different Growth Rates

[目的]探寻遮阴对夏季不同生长速度菜心生长及生理影响。[方法]采用水培方式,以特青迟心(慢生型)、华夏50天(中等)和四九-19(快生型)菜心为材料,以白色遮阳网(透光率62.0%)覆盖为对照(CK),研究黑色遮阳网(透光率38.4%)对不同品种菜心的生长、叶绿素荧光及反射光谱的影响。[结果]黑色遮阳网不利于菜心生长,生长抑制程度表现为四九-19>华夏50天>特青迟心;黑色遮阳网使菜心叶绿素a/b均降低,特青迟心和华夏50天菜心叶绿素含量增加,四九-19叶绿素含量降低;黑色遮阳网使菜心暗适应下的初始荧光(Fo)、暗适应下最大荧光(Fm)和表观电子传递速率(ETR)增加,使暗适应下最大光化学量子效率(Fv/Fm)、光适应条件下的PSⅡ最大光化学量子效率(Fv′/Fm′)、PSⅡ实际光化学量子效率(ΔF/Fm′)和光化学猝灭系数(qP)降低;遮阴提高菜心在近红外波段的光谱反射率。[结论]过度遮阴避免了叶片结构的光损伤,但不能满足菜心生长的光能需求,且对速生品种的影响大于慢生型品种。

[Objective]To explore the effects of shading on the growth and physiology of flowering Chinese cabbage at different growth rates in summer.[Method]The effects of black shading net (light transmittance of 38.4%) on the growth,chlorophyll fluorescence parameters and reflectance spectrum of different varieties of flowering Chinese cabbage were studied by hydroponic culture,using Teqingchixin (slow-growing type),Huaxia 50 d (intermediate-growing type) and Sijiu-19 (fast-growing type) as materials and white shading net (light transmittance of 62.0%) as control (CK).[Result]Black shading net was not conducive to the growth of cabbage,and the degree of growth inhibition was expressed as Sijiu-19 > Huaxia 50 d> Teqingchixin.The black shading net reduced the chlorophyll a/b of all varieties,increased the chlorophyll content of Teqingchixin and Huaxia 50 d,decreased the chlorophyll content of Sijiu-19.The black shading network increased the initial fluorescence ( F o) and maximum fluorescence ( F m) and the electron transfer rate (ETR),but decreased actual photochemical quantum efficiency of PS Ⅱ under light adaptation(Δ F / F m′),maximal photochemical quantum efficiency under dark adaptation( F v/ F m),maximum photochemical efficiency of PSⅡunder light adaptation( F v′/ F m′) and photochemical quenching( q P) of flowering Chinese cabbage.The spectral reflectance of leaf in near infrared band of the black shading network had improved.[Conclusion]Excessive shading could prevent light damage of blade structure,but could not satisfy the light energy demand growth of the flowering Chinese cabbage,and has a greater impact on fast-growing variety than slow-growing variety.