SEASONAL AND AGE-RELATED VARIATION IN THE NEEDLE QUALITY OF 5 CONIFER SPECIES
SEASONAL AND AGE-RELATED VARIATION IN THE NEEDLE QUALITY OF 5 CONIFER SPECIES
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DOI：
10.1007/bf00319402
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发表时间：
1990-01-01
期刊：
影响因子：
2.7
通讯作者：
HATCHER, PE
中科院分区：
文献类型：
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作者：
HATCHER, PE
对樟子松、冷杉云杉等5种针叶树种叶片资源质量(水分、氮、纤维、酚类和韧性)的年龄变化进行了研究。Karsten、Tuga Heterophylla(Rafinesque)Sargent(均为松科)、Chamaecyparis lawsoniana(Murray)Parlatore和Thuja plicata D.Don(均为柏科))。与其他树种的成熟针叶相比，樟子松成熟叶的含氮量、纤维含量和韧性较高，酚类物质含量较低，而异叶铁杉的酚类物质含量较高，纤维和韧性较低。与老针相比，未成熟的针叶具有更高的水分和氮素水平，而更低的纤维和韧性水平。云杉和铁杉未成熟针叶中酚类物质含量较高，随着针叶成熟度的增加，酚类物质含量逐渐降低。到8月中旬，当年针叶中的大多数叶成分水平已稳定在下一年保持的水平。采样显示，在3月至6月期间，成熟针叶中的酚类物质、纤维和水分的浓度有所下降。讨论了这种季节性趋势的可能原因。针叶树的叶成分水平与阔叶树的水平进行了比较。针叶树叶中所有测定成分的浓度较高，但除了针叶针叶的韧性比针叶针叶高6倍外，阔叶和针叶之间的差异小于未成熟针叶和成熟针叶之间的差异。以前的研究已经将针叶树上鳞翅目昆虫的丰度与寄主植物的分类关系联系起来。然而，在这项研究中测量的叶片成分不能很好地预测针叶树之间的分类关系。这些结果表明，鳞翅目昆虫在针叶树上的丰度不受叶片总成分水平的影响，并讨论了其他寄主因子在影响鳞翅目昆虫对针叶树的利用中的作用。
Age changes of foliage resource quality (water, nitrogen, fibre, phenolics and toughness) were studied in five species of conifer (Pinus sylvestris L., Picea abies (L.) Karsten, Tsuga heterophylla (Rafinesque) Sargent (all Pinaceae), Chamaecyparis lawsoniana (Murray) Parlatore and Thuja plicata D. Don (both Cupressaceae)) over a 2-year period in an English forest. Mature foliage of Pinus sylvestris was characterized by higher levels of nitrogen, fibre and toughness, and lower phenolics, and that of Tsuga heterophylla by higher levels of phenolics, and lower fibre and toughness levels, than the mature needles of the other species studied. Immature needles had higher levels of water and nitrogen, and lower levels of fibre and toughness, than older needles. Immature needles of Picea abies and Tsuga heterophylla had a high concentration of phenolics, which decreased with needle maturity. By mid-August, the levels of most of the foliar constituents in current-year needles had stabilized at levels maintained for the next year. Sampling revealed a fall in the concentration of phenolics, fibre and water in mature needles between March and June. Possible reasons for this seasonal trend are discussed. The levels of conifer foliar constituents were compared with levels recorded in broadleaf trees. Conifers had greater concentrations of all measured foliar constituents, but, with the exception of the sixfold greater toughness of conifer needles, the differences between broadleaves and conifers were less than those between the immature and mature conifer needles. Previous studies have related the abundance of Lepidoptera on conifers to hostplant taxonomic relationships. However, the foliar constituents measured in this study were poor predictors of taxonomic relationships between the conifers. It is suggested that the abundance of Lepidoptera on conifers is not determined by levels of general foliar constituents and the role of other hostplant factors in shaping lepidopteran utilization of conifers is discussed.