摘要
光是影响植物生长的重要因子之一。它不仅能够影响植物的光合作用,同时,光还以环境信号的形式作用于植物,通过光敏色素等作用途径调节植物生长、发育和形态建成,使植物更好地适应外界环境。除此之外,光还可以影响植物的初生代谢过程和次生代谢。因此提高植物体内重要次生代谢产物,光的因素不可忽视。少花桂(Cinnamomum pauciflorum)是樟科樟属多年生常绿小乔木,其体内含有精油,鲜叶含油量可达3.5 % ,比黄樟树根含油量高出1倍左右,精油中黄樟油素纯度高达95 %以上。以少花桂为材料,采用人工模拟不同生境的光照条件,探讨光强因子对少花桂生长及精油含量的影响,以求对其生产提供理论指导。通过窗纱遮荫实现对其生境光的控制,研究了光强因子对少花桂幼苗形态结构、水分状况、光合指标、生物量、香桂油含量和纯度的影响。结果表明:随生境相对光照强度的减弱,叶片厚度、叶片上表皮厚度、下表皮厚度、栅栏组织、海绵组织厚度、根冠比等都呈现降低的趋势;而平均单叶面积却呈现出增加的趋势;株叶面积在6 1.5 %的全光照下有所增加,而在33.8%和15 .4 %全光照条件下大幅度减小;遮荫条件下生长的少花桂幼苗根系相对不发达,根冠比小;生境的光照强度会影响植株的水分蒸腾,从而影响含水量。在同样光照下,全光照条件下生?
Light can regulate plants' growth and morphogenesis, and adapt plants to environments via photosynthesis and phytochrome effects. In addition, light may affect primary and secondary metabolism of plants, and light is important in the production of secondary metabolites in plants. Cinnamomum pauciflorum is a perennial evergreen plant species, its leaves have Cinnamomum pauciflorum oil, in which safrol takes the proportion of more than 95%. The paper analyzed the effects of light intensity on morphology, water status, photosynthesis, biomass, oil content and purity of Cinnamomum pauciflorum seedlings. It was shown that leaf thickness, upper epidermis and lower epidermis thickness of leaf, palisade tissue and spongy tissue thickness, and root shoot ratio were decreased with light intensity. while the average area per leaf was increased. Total leaf area of plants under were increased under 61.5% full sunlight, but were decreased greatly under 33.8% and 15.4% full sunlight; Root systems of Cinnamomum pauciflorum seedlings under low light conditions were not developed well, shading decreased Cinnamomum pauciflorum seedlings' root shoot ratio. Light intensity affected water transpiration rate and plants' water content therefore. Under the same conditions, water retentivity of Cinnamomum pauciflorum seedlings under full sunlight was the highest, and that of seedlings under 15.4% full sunlight was the lowest. Light saturation point and light compensation point of Cinnamomum pauciflorum seedlings decreased with decreasing light intensity. CO 2 compensation point of Cinnamomum pauciflorum seedlings under overshading was higher than that of plants under full sunlight. Photorespiration rate and Chlorophyll content of Cinnamomum pauciflorum seedlings were increased with decreasing light intensity, while Chla/Chlb was decreased. Light intensity had significant effects on the growth of Cinnamomum pauciflorum seedlings. Compared with full sunlight, the growth rate in leaf fresh weight of Cinnamomum pauciflorum seedlings under 61.5%、33.8% and 15.4% full sunlight were 1.6,1.2 and 0.77 times, respectively. Oil Contents of Cinnamomum pauciflorum seedlings under 61.5% and 33.8% full sunlight were higher than that of plants under full sunlight by 5%,but oil content of Cinnamomum pauciflorum seedlings under 15.4% full sunlight was lower than that of plants under full sunlight by 5%. With respect to the proportion of safrol in Cinnamomum pauciflorum oil,Cinnamomum pauciflorum seedlings under 33.8% and 15.4% full sunlight had larger quantity than others. Therefore, it seems that slight shading(under 61.5% full sunlight) could increase leaf biomass and consequently Cinnamomum pauciflorum oil content, heavy shading(under 33.8% and 15.4% full sunlight)could increase purity of safrol.
出处
《生态学报》
CAS
CSCD
北大核心
2005年第5期1159-1164,共6页
Acta Ecologica Sinica
基金
国家自然科学基金资助项目 (3 93 3 0 0 5 0)~~
关键词
少花桂
光强因子
光合指标
黄樟油素
Cinnamomum pauciflorum
light intensity
photosynthesis indexes
safrol
