Physiological and morphological variation in Metrosideros polymorpha, a dominant Hawaiian tree species, along an altitudinal gradient: the role of phenotypic plasticity
Physiological and morphological variation in Metrosideros polymorpha, a dominant Hawaiian tree species, along an altitudinal gradient: the role of phenotypic plasticity
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DOI：
10.1007/s004420050367
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发表时间：
1998-01-01
期刊：
影响因子：
2.7
通讯作者：
Vitousek, PM
中科院分区：
文献类型：
--
作者：
Cordell, S;Goldstein, G;Vitousek, PM
Metrosideros polymorpha是夏威夷生态系统中的优势树种，占据了广泛的栖息地。补充领域和共同花园的研究M。在两个不同基质年龄的海拔梯度上对多形藻种群进行了研究，以确定该物种的大的表型变异是由遗传差异还是由环境条件引起的表型修饰决定的。一些特征，包括生理生态行为和解剖特征，在很大程度上是由环境引起的。然而，其他特征，特别是叶形态，似乎主要是由遗传背景决定的。普通园林植物的平均净同化率（5.8 μ mol CO_2·m ~（-2）·s ~（-1））和平均气孔导度（0.18 mol H_2O·m ~（-2）·s ~（-1））高于田间植物（3.0 μ mol CO_2·m ~（-2）·s ~（-1）和0.13 mol H_2O·m ~（-2）·s ~（-1））。大多数常见园林植物的叶片δ（13）C在原产地之间是相似的，平均值为-26.9ppm。相比之下，田间植物叶片δ（13）C的平均值从低海拔的-29.5 ‰增加到高海拔的-24.8 ‰。单位面积的叶质量随海拔高度的增加而显著增加，但普通园林植物的值范围要窄得多（普通园林植物为211-308 g m（-2），而田间植物为107-407 g m（-2））。普通园林植物叶面积上测得的氮含量范围为1.4 g m（-2）至2.4 g m（-2），田间植物为0.8 g m（-2）至2.5 g m（-2）。光合氮利用效率（PNUE）下降了50%，在田间植物和只有20%的植物从年轻的基板在普通花园海拔的增加。这是由于普通园林植物的净CO2同化率较高。叶组织和细胞层的厚度，和程度的叶柔毛增加显着与海拔在外地的植物，而在常见的园林植物，与海拔的起源的变化要窄得多，或完全没有。形态特征，如叶的大小，叶柄的长度，节间的长度随着海拔的增加而下降，并保留在常见的花园中生长时，这些性状的潜在遗传基础。环境引起的生理和解剖特征的变异和遗传决定的形态特征的变异相结合，使夏威夷M。polymorpha获得和支配了在其他树种中没有观察到的极其广泛的生态分布。
Metrosideros polymorpha, a dominant tree species in Hawaiian ecosystems, occupies a wide range of habitats. Complementary field and common-garden studies of M. polymorpha populations were conducted across an altitudinal gradient at two different substrate ages to ascertain if the large phenotypic variation of this species is determined by genetic differences or by phenotypic modifications resulting from environmental conditions. Several characteristics, including ecophysiological behavior and anatomical features, were largely induced by the environment. However, other characteristics, particularly leaf morphology, appeared to be mainly determined by genetic background. Common garden plants exhibited higher average rates of net assimilation (5.8 mu mol CO2 m(-2) s(-1)) and higher average stomatal conductance (0.18 mol H2O m(-2) s(-1)) than their field counterparts (3.0 mu mol CO2 m(-2) s(-1), and 0.13 mol H2O m(-2) s(-1) respectively). Foliar delta(13)C of most common-garden plants was similar among sites of origin with an average value of -26.9 parts per thousand. In contrast, mean values of foliar delta(13)C in field plants increased substantially from -29.5 parts per thousand at low elevation to -24.8 parts per thousand at high elevation. Leaf mass per unit area increased significantly as a function of elevation in both field and common garden plants; however, the range of values was much narrower in common garden plants (211-308 g m(-2) for common garden versus 107-407 g m(-2) for field plants). Nitrogen content measured on a leaf area basis in common garden plants ranged from 1.4 g m(-2) to 2.4 g m(-2) and from 0.8 g m(-2) to 2.5 g m(-2) in field plants. Photosynthetic nitrogen use efficiency (PNUE) decreased 50% with increasing elevation in field plants and only 20% in plants from young substrates in the common garden. This was a result of higher rates of net CO2 assimilation in the common garden plants. Leaf tissue and cell layer thickness, and degree of leaf pubescence increased significantly with elevation in field plants, whereas in common garden plants, variation with elevation of origin was much narrower, or was entirely absent. Morphological characteristics such as leaf size, petiole length, and internode length decreased with increasing elevation in the field and were retained when grown in the common garden, suggesting a potential genetic basis for these traits. The combination of environmentally induced variability in physiological and anatomical characteristics and genetically determined variation in morphological traits allows Hawaiian M. polymorpha to attain and dominate an extremely wide ecological distribution not observed in other tree species.