—Seedlings of Salvia coccinea, S. splendens and S.
viridis were grown at 100, 50, 25 and 5% of full sunlight level to
determine the influence of irradiance level on their grown and
photosynthesis. For all species the shoot length and dry weight
of wholeplant were decreased at 25% sunlight, but there was
little defference in them between at 50 and 100% sunlight. Total
leaf area tended to increase at 50% sunlight in S. splendens and
S. viridis and to decrease at 25% sunlight in S.coccinea. Leaf
area ratio increased with decreasing light intensity in every
species, and the degree of increase was the least in S.coccinea.
With decreasing light intensity, leaves became thinner and the
specific leaf weight decreased for all species. Chlorophyll
content and photosynthetic rate more decreased at 25% than
those at 100 and 50% sunlight in S. splendens and S. viridis.
There were little differences both in the chlorophyll content and
photosynthesis among these light intensities in S.coccinea. This
indicates that S.coccinea has higher adaptability to low
irradiance than other two species. Under weak light condition
the stomatal conductance increased for all species. At 5%
sunlight, the plant dry weight was less than about 90% of that of
100% sunlight and photosynthetic rate almost decreased to the
light compensation point.
—Irradiance level, photosynthesis, Salvia.
Y. Koike is with the Faculty of Agriculture, Tokyo University of
Agriculture, Atsugi, Kanagawa, Japan (e-mail: koike@ nodai.ac.jp).
Cite:Yasuhiko Koike, "Effects of Irradiance Level on the Growth and Photosynthesis of Salvia," International Journal of Environmental Science and Development vol. 4, no. 5, pp. 479-482, 2013.