不同栽植密度下欧美杨叶片耐荫性与生物累积量的关系

为阐明不同栽植密度下欧美杨无性系树冠叶片耐荫性与生物累积量的关系,选择高密度(2 m×3 m)和低密度(2 m×5 m)栽植的不同亲本的5个欧美杨无性系为研究对象,测量了生物量、树冠结构、叶面积指数及光合参数。结果表明:(1)不同无性系对栽植密度有不同的反应;(2)具有较高生物量的欧美杨无性系树冠叶片在高、低栽植密度下均表现出较强的耐荫性特征;(3)树冠耐荫性在不同密度中表现出差异性,在低密度栽植中,树冠上层耐荫性与生物量和叶面积指数关系密切;在高密度栽植中,树冠上、下层叶片耐荫性与生物量和叶面积指数关系密切;(4)树冠耐荫性特征受亲本和环境的共同影响,由低密度到高密度,具有较高生物量的03-04-97、03-04-111、03-04-171树冠中下层叶片光补偿点和暗呼吸速率大幅度降低。该研究结果可为选择适合高密度栽植的欧美杨无性系提供数据和理论支持。

The Relationship of Shade Tolerance of Poplar and Biomass Production under Different Plantation Density

To clarify the relationship between the response of crown leaves to shade environment and biomass production, five genotypes of Populus×euramericana with different parents planted in two densities (2 m×3 m, 2 m×5 m) were chosen and the biomass production, crown depth, crown width, LAI and photosynthesis light response parameters were investigated. The results are as follows: (1) The response to weak light varied among genotypes. (2) The Genotypes 03-04-97,03-04-111 and 03-04-171 showed a high shade tolerance ability and had the highest biomass production in high density plantation. (3) The shade tolerance of genotypes 03-04-97,03-04-111 and 03-04-171 was different under different plantation density. Compared with the density 2 m×5 m, the crown leaves of middle and lower layer showed higher ability of shade tolerance. (4) The interaction between shade tolerance and biomass varied under different plantation density, the shade tolerance of upper layer had significant affections on biomass under the density 2 m×5 m, however, the shade tolerance of upper and lower layers played an important role in biomass production under the density 2 m×5 m. (5) The shade tolerance was affected by environment and heritability. The light compensation point (LCP) and respiration rate (Rd) of the genotypes with high biomass production was significant lower in 2 m×3 m compared with 2 m×5 m. These results could be used to select genotype for high density and short rotation plantation.