PATTERNS OF WATER-USE AND THE TISSUE WATER RELATIONS IN THE DIOECIOUS SHRUB, SALIX-ARCTICA - THE PHYSIOLOGICAL-BASIS FOR HABITAT PARTITIONING BETWEEN THE SEXES
PATTERNS OF WATER-USE AND THE TISSUE WATER RELATIONS IN THE DIOECIOUS SHRUB, SALIX-ARCTICA - THE PHYSIOLOGICAL-BASIS FOR HABITAT PARTITIONING BETWEEN THE SEXES
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DOI：
10.1007/bf00384312
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发表时间：
1989-01-01
期刊：
影响因子：
2.7
通讯作者：
BLISS, LC
中科院分区：
文献类型：
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作者：
DAWSON, TE;BLISS, LC
在加拿大的高北极，北极柳，雌雄异株，矮柳表现出显著的性别空间隔离。总体性别比例偏向于雌性，雌性植物在潮湿，高营养，但土壤温度较低的栖息地尤其常见。相比之下，雄性植物在更干燥和低营养的栖息地中占主导地位，土壤温度更高，容易发生干旱。与不同性别生境差异相关的是不同性别间气孔对水蒸气导度测量的水分利用的季节和日模式差异以及组织体水分关系的差异。在湿润生境中，当土壤和根温较低（< 0.4℃）时，雌株的气孔导度(g)高于雄株。相反，在干性生境中，在低土壤水势和高叶片-空气蒸气压梯度下，雄株保持较高的g值，叶片水势（. ph .leaf）较低。W)与女性相比。雌性植株的正碳同位素比值高于雄性植株，这表明雌性植株叶片内部二氧化碳浓度较低，水分利用效率可能高于雄性植株。组织渗透性和弹性也存在性别差异。雄性植株在接近组织完全水化和膨胀损失点时表现出较低的组织渗透电位，并且比雌性植株具有较低的组织弹性模量（较高的组织弹性）。男性也表现出比女性更强的渗透调节能力。这些特性使得雄性植株在较低的组织含水量和. phi下保持较高的组织膨胀压力。叶子在一天的过程中。特定的分布和生理生态特征也与湿生境雌性和干生境雄性的总生长量和繁殖力有关。两性间的生理差异在所有生境中都存在。这些结果以及从生长室研究中获得的结果表明，性别特异性差异具有潜在的遗传基础。根据这些数据，我们推测，维持雌雄间差异的选择可能与生殖的不同成本有关，而生殖成本最容易通过生理专业化和不同条件下两性栖息地的空间隔离来实现。
Within the high arctic of Canada, Salix arctica, a dioecious, dwarf willow exhibits significant spatial segregation of the sexes. The overall sex ratio is female-biased and female plants are especially common in wet, higher nutrient, but lower soil temperature habitats. In contrast, male plants predominate in more xeric and lower nutrient habitats with higher soil temperatures that can be drought prone. Associated with the sex-specific habitat differences were differences in the seasonal and diurnal patterns of water use as measured by stomatal conductance to water vapor and the bulk tissue water relations of each gender. Within the wet habitats, female plants maintained higher rates of stomatal conductance (g) than males when soil and root temperatures were low (< 4 .degree.C). In contrast, within the xeric habitats, male plants maintained higher g and had lower leaf water potentials (.PHI.leaf) at low soil water potentials and a high leaf-to-air vapor pressure gradient (.DELTA. w) when compared to females. Female plants had more positive carbon isotope ratios than males indicating a lower internal leaf carbon dioxide concentration and possibly higher water use efficiency relative to males. Tissue osmotic and elastic properties also differed between the sexes. Male plants demonstrated lower tissue osmotic potentials near full tissue hydration and at the turgor loss point and a lower bulk tissue elastic modulus (higher tissue elasticity) than female plants. Males also demonstrated a greater ability to osmotically adjust on a diurnal basis than females. These properties allowed male plants to maintain higher tissue turgor pressures at lower tissue water contents and .PHI.leaf over the course of the day. The specific distributional and ecophysiological characteristics were also correlated with greater total plant growth and higher fecundity of females in wet habitats, and males in xeric habitats respectively. The intersexual differences in physiology persisted in all habitats. These results and those obtained from growth chamber studies suggest that sex-specific differences have an underlying genetic basis. From these data we conjecture that selection maintaining the intersexual differences may be related to different costs associated with reproduction that can be most easily met through physiological specialization and spatial segregation of the sexes among habitats of differing conditions.