Defense characteristics of seral deciduous broad-leaved tree seedlings grown under differing levels of CO2 and nitrogen
Defense characteristics of seral deciduous broad-leaved tree seedlings grown under differing levels of CO2 and nitrogen
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DOI：
10.1007/s10144-005-0236-x
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发表时间：
2005
影响因子：
1.7
通讯作者：
T. Koike;H. Tobita;T. Shibata;S. Matsuki;K. Konno;M. Kitao;N. Yamashita;Y. Maruyama
中科院分区：
文献类型：
--
作者：
T. Koike;H. Tobita;T. Shibata;S. Matsuki;K. Konno;M. Kitao;N. Yamashita;Y. Maruyama
在日本北方的阔叶混交林中，有大量的几种食草动物。食草动物的生命在很大程度上取决于食物叶的质量。随着大气CO2和氮沉降的增加，叶片质量也在发生变化。以4种落叶阔叶树（桤木、桦树、橡树和枫树）幼苗为材料，在2种CO2浓度和2种营养水平的4种组合下进行叶片防御特性研究。为了评估四个树种的相对防御能力，我们使用野蚕（Erisan;一个通才草食动物）作为生物测定材料。除桤木外，以高CO2和贫瘠土壤条件下饲养的幼苗叶为饲料的家蚕存活率和寿命（ML 50）最低，而以大气CO2和肥沃土壤条件下生长的幼苗叶为饲料的家蚕存活率和寿命（ML 50）最长，尤其是桦树和枫树。Erisan的寿命依次为桦树、橡树和枫树。用桤木叶喂养的Erisan的寿命与CO2水平无关，并且在贫瘠土壤条件下生长的桤木幼苗的寿命更长。桤木是一种放线根生植物，能将大气中的氮固定在由放线菌Frankiasp形成的根瘤中。在高CO2条件下，从寄主植物获得的大量光合产物会增强共生微生物的活性，从而改善家蚕的食物质量。除桤木外，其它树种的叶片化学性状，尤其是C/N比，均影响着蓖麻蚕的ML 50。
Mixed broad-leaved forests are abundantly populated by several kinds of herbivore species in northern Japan. The life of herbivores depends strongly on the quality of food leaves. Leaf quality is changing with increasing atmospheric CO2and nitrogen deposition. Four seral species of deciduous broad-leaved tree seedlings (alder, birch, oak and maple) were raised in all four combinations of two levels of CO2and two levels of nutrient, to examine foliar defense traits. To evaluate the relative defense capacity of the four tree species, we used wild silkworms (Erisan; a generalist herbivore) as a bioassay material. Except with alder, the survival rate and longevity (ML50) of the silkworms were least when they were fed with leaves of seedlings raised under high CO2and infertile soil conditions, and longest on a diet of leaves grown in ambient CO2and fertile soil, especially in birch and maple. The longevity of Erisan decreased in the order birch, oak, and maple. The longevity of Erisan fed with alder leaves was independent of CO2levels and was longer on alder seedlings grown in infertile soil conditions. Alder is an actinorhizal plant that can fix atmospheric nitrogen in root nodules formed by the actinomycetesFrankiasp. The activity of symbiotic microbes would have been enhanced by the greater amount of photosynthates received from the host plants at high CO2, improving the food quality for the silkworms. It was concluded that in all but alder, leaf chemical traits, especially C/N ratio, affect the ML50of Erisan larvae.