open access

https://hdl.handle.net/2115/49706

Growth and photosynthetic traits of hybrid larch F1 (Larix gmelinii var. japonica x L. kaempferi) under elevated CO2 concentration with low nutrient availability

英語

photosynthetic adjustment

2011-09

Oxford University Press

Tree Physiology

31(9)

965-975

The hybrid larch F1 (Larix gmelinii var. japonica x Larix kaempferi) is considered as one of the most important tree species not only for timber production but also as an afforestation material for severe conditions such as infertile soil. To predict the ability of hybrid larch F1 as an afforestation material under potential climates in the future, it is important to understand the response of hybrid larch F1 to elevated CO2 concentration ([CO2]) under low nutrient availability. Three-year-old seedlings of hybrid larch F1 were grown under two different levels of [CO2], 360 (ambient) and 720 μmol mol^[-1] (elevated), in combination with two different levels of nitrogen (N) supply (0 and 30 kg ha^[-1]) for one growing season. Elevated [CO2] reduced the maximum rates of carboxylation and electron transport in the needles. Net photosynthetic rates at growth [CO2] (i.e., 360 and 720 μmol mol^[-1] for ambient and elevated treatment, respectively) did not differ between the two CO2 treatments. Reductions in the N content and the N use efficiency to perform photosynthetic functions owing to the deficiency of nutrients other than N, such as P and K, and/or increase of cell wall mass were considered as the factors of photosynthetic down-regulation under elevated [CO2], whereas stomatal closure little affected the photosynthetic down-regulation. Although we observed strong down-regulation of photosynthesis, the dry matter increase of hybrid larch F1 seedlings was enhanced under elevated [CO2]. This is mainly attributable to the increase in the amount of needles with increasing the number of sylleptic branches. These results suggest that elevated CO2 may increase growth of hybrid larch F1 even under low nutrient availability, and that this increase may be regulated by both changes in crown architecture and in needle photosynthesis, which is mainly affected by not stomatal limitation but by biochemical limitation.

学術雑誌論文

Accepted Manuscript

This is a pre-copy-editing, author-produced PDF of an article accepted for publication in Tree Physiology following peer review. The definitive publisher-authenticated version Tree Physiol (2011) 31 (9): 965-975 is available online at: http://treephys.oxfordjournals.org/content/31/9/965

0829-318X