Winter leaf loss in the New Zealand woody flora
Winter leaf loss in the New Zealand woody flora
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新西兰木本植物区系冬季落叶
DOI：
10.1080/0028825x.2004.9512887
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发表时间：
2004
期刊：
影响因子：
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通讯作者：
R. Allen
中科院分区：
文献类型：
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作者：
M. McGlone;R. Dungan;G. Hall;R. Allen
约27种（C。5%）的新西兰木本植物群在冬季有明显的落叶现象，尽管只有10种植物是持续完全落叶的，并且没有广泛的植被类型以它们为主。没有夏季落叶树种。在大多数情况下，落叶习性似乎是在新西兰境内独立地从祖先或具有短叶寿命的移民进化而来的。新西兰落叶或半落叶物种通常在整个生长季节失去大量的叶子，叶子的损失通常在整个冬季逐渐减少，但霜冻会加速。新西兰的落叶习性往往是叶或芽水平的特征，反映了叶寿命短和冬季对单个芽的压力，而不是植物冠层组织的系统特征。落叶的程度随分类群、植物年龄、气候和土壤肥力而变化。对南岛共同出现的完全落叶（Fuchsia excorticata）和半落叶（Aesthetelia serrata）树木的生理研究表明，Fuchsia较高的生长季节生产力弥补了冬季放弃的碳增益。然而，只有在最冷的地方，紫红色才比鸢尾花更受青睐。除了南岛的一些内陆盆地外，新西兰的冬天比全球有利于落叶物种的冬天温和，这是落叶物种发生率低的主要原因。即便如此，一些落叶物种在各地都很常见。新西兰的落叶乔木和灌木通常生长迅速，是最近冲积层或碎屑中发育的营养丰富的土壤上的连续或森林边缘栖息地的特征。大多数新西兰森林土壤的养分状况相对较低，使得落叶物候具有必要的高养分周转，比养分保存的万年青物候竞争力更低。落叶物种通常也是分叉的，或者有近亲，并且与这种生长形式共享对营养丰富的土壤的偏好。这两种习惯之间的密切关系表明，两者都是部分适应高生产力叶片的植物对压力气候的适应。
Abstract Approximately 27 species (c. 5%) of the New Zealand woody flora have a marked loss of leaves in winter, although only 10 species are consistently fully deciduous and no extensive vegetation type is dominated by them. There are no summer deciduous species. The deciduous habit appears in most cases to have evolved independently within New Zealand from either ancestors or immigrants with short leaf life spans. New Zealand deciduous or semideciduous species typically lose substantial numbers of leaves throughout the growing season, and leaf loss is often gradual throughout winter but accelerated by frost. The deciduous habit in New Zealand tends to be a leaf‐ or shoot‐level feature reflecting short leaf life spans and winter stress on individual shoots, rather than a systematic feature of the canopy‐level organisation of the plant. Degree of deciduousness varies with taxon, plant age, climate, and soil fertility. A physiological study of co‐occurring fully deciduous (Fuchsia excorticata) and semideciduous (Aristotelia serrata) trees in the South Island established that higher growing‐season productivity of Fuchsia compensated for carbon gain forgone over winter. However, Fuchsia was significantly favoured over Aristotelia only on the coldest sites. Aside from some inland basins of the South Island, New Zealand has milder winters than those that favour deciduous taxa globally, and this is the primary reason for the low incidence of deciduous species. Even so, a number of deciduous species are common throughout. New Zealand deciduous trees and shrubs are typically fast growing and are characteristic of seral or forest marginal habitat on nutrient‐rich soils developed in recent alluvium or debris. The relatively low nutrient status of most New Zealand forest soils makes a deciduous phenology, with its necessarily high turnover of nutrients, less competitive than a nutrient‐conserving evergreen phenology. Deciduous species are often also divaricating, or have close relatives that are, and share a preference for nutrient‐rich soils with this growth form. This strong relationship between the two habits suggests both are, in part, adaptations to stressful climates by plants with high‐productivity leaves.