Kume, A. & Tanaka, C. Ecol. Res. (1996) 11: 207. doi:10.1007/BF02347687
The adaptation ofCamellia rusticana, an evergreen broad-leaved shrub found in areas of heavy snowfall in Japan, to heavy snowfall environments, and the mechanisms by which it is damaged in winter above the snow, were investigated. The stomatal response and photosynthetic characteristics ofC. rusticana were compared to those ofCamellia japonica found in areas of light snowfall. In field conditions, the mean net photosynthesis ofC. rusticana at photon flux density (PFD) over 200 μmol m−2s−1 (Pn(>200). was 50% larger than that ofC. japonica, but in both light saturated and CO2 saturated conditions, the O2 evolution rate (Pc) ofC. rusticana was not different from that ofC. japonica. Mean leaf conductance at PFD over 200 μmol m−2s−1 (gl(>200)) was about 100% larger than that ofC. japonica in the field. The Pn(>200)) was 50% ratio ofC. rusticana was 37% higher than that ofC. japonica which suggests thatC. rusticana's larger Pn(>200) can be explained by its larger gl(>200). WhenC. rusticana trees wintering underneath the snow were projected above it, the leaves of these plants showed serious drought within five days in non-freezing conditions. Their Pc and the maximum stomatal conductance decreased by half and did not recover. The leaves ofC. rusticana showed larger gl(>200) and a less sensitive stomatal response to the decrease of leaf water potential than that ofC. japonica. The stomata characteristics ofC. rusticana caused larger net photosynthesis than that ofC. japonica during the no snow period, and caused the need for snow cover in winter as protector from winter drought.
Camellia rusticanasnow coverSea of Japanstomatawinter drought