Morphological and Physiological Responses of Three California Oak Species to Shade
Morphological and Physiological Responses of Three California Oak Species to Shade
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三种加州橡树品种对遮荫的形态和生理反应
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发表时间：
1992
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通讯作者：
R. Callaway
中科院分区：
文献类型：
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作者：
R. Callaway
物种间对遮荫的形态和生理反应的差异通常与中生林地的生态作用相对应，但在半干旱林地和稀树草原中很少被研究。我比较了三种加州栎树在三种实验遮荫处理下的地上部质量、根质量、根冠比、主根伸长率、全苗叶面积、全苗比叶面积、叶面积比和光合作用能力：全光照({
M i}_{ext{Full}})$，全日照的50%$({
M i}_{50\%})$，和10%的全日照$({
M i}_{10\%})$。尽管不同遮荫处理的幼苗生物量分配到叶、茎和根的百分比在种内没有差异，但种间生物量分配的差异、遮荫诱导的叶片形态变化、整株幼苗的光合作用能力和主根伸长率可能是文献报道的黑栎耐荫性和栓皮栎幼苗耐荫性的部分原因。然而，在阴凉处招募的杜鹃幼苗的形态和生理反应与杜鹃相似，不能很好地解释文献中报道的杜鹃幼苗在阴凉处的高募集现象。${
苗木根重分别降低46%和60%，苗木总生物量和根冠比也有相似的降低。遮荫不影响黑杨幼苗的全苗生物量、根重和根冠比。总苗叶面积在遮荫条件下不增加，而在遮荫条件下增加。
M i}_{10\%}q$。仙人掌幼苗的叶面积增加了一倍。黑荆幼苗的比叶面积和叶面积比的增加幅度也大大高于其他两个树种。对于生长在${
品种间单位叶面积的光合能力无显著差异，但150μEm-2 S-1的整株光合能力为111.3亩。
M摩尔}{
Mg}^{-1}{
S为生长在${-1}上的黑杨放出氧气。
与34.7美元和51.3美元相比
M摩尔}{
Mg}^{-1}{
M S，分别为小叶栎属和豆科栎属。${
M i)时，侧柏幼苗的主根伸长率是对照的63%。
M i}_{ext{Full}}$，而在${{}}时，豆杉和小叶栎伸长率分别下降到54%和26%
M i}_{ext{Full}}$。遮荫适应的这种差异可能部分解释了种间生态功能的差异，包括与其他物种的相互作用、补充模式和演替作用。
Interspecific differences in morphological and physiological responses to shade commonly correspond to ecological roles in mesic woodlands but rarely have been studied in semiarid woodlands and savannas. I compared shoot mass, root mass, root: shoot ratio, taproot elongation rate, whole-seedling leaf area, whole-seedling specific leaf area, leaf area ratio, and photosynthetic capacity among three species of California oaks in three experimental shade treatments: full sunlight $({
m I}_{ ext{full}})$, 50% of full sunlight $({
m I}_{50\%})$, and 10% of full sunlight $({
m I}_{10\%})$. Although there were no intraspecific differences in the percentage of seedling biomass allocated to leaves, stems, and roots in different shade treatments, interspecific differences in biomass allocation, shade-induced changes in leaf morphology, whole-seedling photosynthetic capacities, and taproot elongation rates may explain, in part, shade tolerance of Quercus agrifolia and shade intolerance of Q. lobata seedlings reported in the literature. However, morphological and physiological responses of Q. douglasii, which recruits in shade, were similar to those of Q. lobata and do not adequately explain the high recruitment of Q. douglasii seedlings in shade reported in the literature. At ${
m I}_{10\%}$, root weights of Q. lobata and Q. douglasii seedlings decreased by 46% and 60%, respectively, and showed similar decreases in total seedling biomass and root: shoot ratios. Shade did not affect whole-seedling biomass, root weight, or root: shoot ratio of Q. agrifolia seedlings. Total seedling leaf area of Q. lobata and Q. douglasii did not increase in shade, whereas at ${
m I}_{10\%} Q$. agrifolia seedlings doubled in leaf area. Specific leaf area and leaf area ratio of Q. agrifolia seedlings also increased substantially more than the other two species. For seedlings grown at ${
m I}_{10\%}$, photosynthetic capacity per leaf area did not differ among species, but whole-seedling photosynthetic capacity at 150 μ E m-2 s-1 was $111.3 mu {
m mol} {
m g}^{-1} {
m s}^{-1}$ of oxygen evolved for Q. agrifolia grown at ${
m I}_{10\%}$ compared with 34.7 and $51.3 mu {
m mol} {
m g}^{-1} {
m s}^{-1}$ for Q. lobata and Q. douglasii, respectively. At ${
m I}_{10\%}$, the taproot elongation rate of Q. agrifolia seedlings was 63% of the rate at ${
m I}_{ ext{full}}$, while Q. douglasii and Q. lobata elongation rates dropped to 54% and 26% of rates at ${
m I}_{ ext{full}}$, respectively. This variation in shade acclimation may partially explain interspecific differences in ecological functions, including interactions with other species, patterns of recruitment, and successional roles.