open access

https://hdl.handle.net/2115/4866

Defense characteristics of seral deciduous broad-leaved tree seedlings grown under differing levels of CO2 and nitrogen

英語

silkworm

2006-01

Springer-Verlag Tokyo Inc.

Population Ecology

48(1)

23-29

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 CO2 and 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 CO2 and 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 CO2 and infertile soil conditions, and longest on a diet of leaves grown in ambient CO2 and 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 CO2 levels and was longer on alder seedlings grown in infertile soil conditions. Alder is an actinorrhizal plant that can fix atmospheric nitrogen in root nodules formed by the actinomycetes Frankia sp. 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. All but alder, leaf chemical traits especially C/N ratio were concluded to affect ML50 of Erisan larvae.

学術雑誌論文

Accepted Manuscript

The original publication is available at www.springerlink.com

1438-3896