油茶林下套种伞房决明的密度效应研究

Effect of Interplanting Density of Cassia corymbose in Camellia oleifera Stand on Photosynthetic Characteristics and Biomass

伞房决明Senna corymbosa,不仅具有护土保水、适应性广的特点,还可以作为蜜源植物。2020年3—4月,在浙江省遂昌县湖山乡栽植6 a的油茶Camellia oleifera幼林林地的林间空隙种植10株·m^(-2)(LD)和40株·m^(-2)(HD)2种密度伞房决明,并于当年10月对其生长量开展调查,探索油茶林下不同密度种植伞房决明的生长效应。结果表明,伞房决明在HD下的株高显著高于LD下的(P<0.05),2种密度下生物量分配也存在明显差异,在LD下根系和果实占总生物量的比例更高,分别是HD下的1.45倍和2.69倍,而枝干生物量占比则仅为后者的70.6%。不同种植密度也影响了叶片的生长特征,在LD下有更大的叶片厚度,更小的单叶周长、面积和比叶面积(P <0.05)。不同密度间叶片的光合速率差异不显著,但在HD下有更高的气孔导度、蒸腾速率和胞间CO_(2)浓度(P <0.05)。

Experiments were conducted on interplanting of Cassia corymbosa with two densities(LD: 10 plants per m^(2) and HD: 40 plants per m^(2)) in Camellia oleifera plantation with 6 years cultivation in Suichang, Zhejiang province during March and April 2020. Determination was implemented in October on the growth of C. corymbosa. The results showed that height growth of C. corymbosa in HD was significantly higher than that in LD(P <0.005), and it had significant difference in the biomass distribution between two densities. Under LD treatment, the proportion of root and fruit was 1.45 and 2.69 times of HD treatment, while the proportion of stem and branch was only 70.6% of the latter. There was larger leaf thickness, smaller leaf circumference, leaf area and specific leaf area under LD treatment(P<0.05). There was no significant difference in photosynthetic rate among different densities(P>0.05), but higher stomatal conductance, transpiration rate and intercellular CO_(2) concentration in HD treatment(P < 0.05).