LEAF FRACTURE-TOUGHNESS AND SCLEROPHYLLY - THEIR CORRELATIONS AND ECOLOGICAL IMPLICATIONS
LEAF FRACTURE-TOUGHNESS AND SCLEROPHYLLY - THEIR CORRELATIONS AND ECOLOGICAL IMPLICATIONS
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DOI：
10.1111/j.1469-8137.1992.tb01131.x
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发表时间：
1992-08-01
期刊：
影响因子：
9.4
通讯作者：
TURNER, IM
中科院分区：
文献类型：
--
作者：
CHOONG, MF;LUCAS, PW;TURNER, IM
采用仪器化切割技术，沿“最小韧性”路径测量了生长在新加坡的42种热带树种的太阳叶片的断裂韧性。还进行了冲压和模具（压模）测试。肋间材料进行了分析，粗纤维和粗蛋白质（总氮浓度x 6.25）和两者的比例，硬叶指数，计算每个物种。叶解剖进行了检查，并计算了比叶面积。其中37个物种来自3个可定义的植物群落，即红树林，（未退化地点的次生林）和Adinandra belukar 42个树种的断裂韧性与硬叶指数呈极显著正相关（R~2 = 0.43，P <0.001），主要是由于粗纤维含量与韧性的高度相关性所致。断裂韧性与椎板组织背腹厚度不相关，但高韧性与厚壁组织束鞘和鞘延伸的存在明显相关。对10种红树林的26片叶片的断裂路径分析表明，如果排除白骨壤，则脉所占面积分数与断裂韧性之间存在高度相关性。其他9个物种的回归方程估计的断裂韧性的静脉组织和椎板基质的6053和327 J m-2分别。冲压和模具的测试结果只有相关性以及切割测试时，值除以叶片thicken.The蛋白质纤维的比例在一片叶子（的指数的倒数）已被确立为一个很好的预测叶的适口性和消化性的通才咀嚼食叶动物。断裂韧性和一个大样本的硬叶指数之间的高度相关性表明，叶韧性可以作为一个直接的线索，用于确定食草动物觅食策略的食物质量的因素。
The fracture toughness of sun-leaves of 42 tropical tree species growing in Singapore was measured along a 'least tough' path using an instrumented cutting technique. Punch-and-die (penetrometer) tests were also conducted. Intercostal material was analyzed for crude fibre and crude protein (total nitrogen concentration x 6.25) and the ratio of the two, the index of sclerophylly, calculated for each species. Leaf anatomy was examined and specific leaf area was calculated. Thirty-seven of the species were from three definable plant communities, namely mangroves, trema belukar (secondary forest on undegraded sites) and adinandra belukar (secondary forest on highly degraded soils).There was a highly significant positive correlation between fracture toughness and index of sclerophylly for the 42 species (R2 = 0.43, P < 0.001) brought about largely by a high correlation between toughness and crude fibre content. Fracture toughness was not correlated with lamina tissue dorsi-ventral thickness but high toughness was clearly associated with the presence of sclerenchyma bundle sheaths and sheath extensions. Analysis of the fracture path for 26 leaves of ten mangrove species showed a high correlation between the area fraction occupied by veins and fracture toughness if one species, Avicennia rumphiana, was excluded. The regression equation for the other nine species gave estimates of the fracture toughness of vein tissue and lamina matrix of 6053 and 327 J m-2 respectively. Punch-and-die test results only correlated well with the cutting tests when values were divided by lamina thickness.The ratio of protein to fibre in a leaf (the reciprocal of the index of sclerophylly) has been established as a good predictor of leaf palatability and digestibility to generalist chewing folivores. The high correlation between fracture toughness and the index of sclerophylly for a large sample suggests that leaf toughness could be the factor used as a proximate cue for determining food quality in herbivore foraging strategies.