Studies on the response of trees to drought- and heat-stress under climate changes

Research Project

Project/Area Number	08456074
Research Category	Grant-in-Aid for Scientific Research (B)
Allocation Type	Single-year Grants
Section	一般
Research Field	林学
Research Institution	Chiba University
Principal Investigator	KOBAYASHI Tatsuaki Chiba University, Fac.of Horticulture, Assoc.Prof., 園芸学部, 助教授 (40178322)
Co-Investigator(Kenkyū-buntansha)	OKANO Chiharu Chiba University, Center for Environmental Remote Sensing, Instructor, 助手 (20272354) TAKAGAKI Michiko Chiba University, Fac.of Horticulture, Lecturer, 園芸学部, 講師 (00206715) NAKAYAMA Keiichi Chiba University, Fac.of Horticulture, Professor, 園芸学部, 教授 (90009697)
Project Period (FY)	1996 – 1997
Project Status	Completed (Fiscal Year 1997)
Budget Amount *help	¥6,700,000 (Direct Cost: ¥6,700,000) Fiscal Year 1997: ¥500,000 (Direct Cost: ¥500,000) Fiscal Year 1996: ¥6,200,000 (Direct Cost: ¥6,200,000)
Keywords	drought damage / heat stress / water stress / photosynthesis / tree / mathematical model / stress monitoring / 光合成過程 / 数理モデル / 樹種特性 / 光合成パラメータ
Research Abstract	1.Effects on photosynthetic processes The responses to heat and water stress were studied for Stewartia pseudocamellia (Sp), Stewartia monadelpha (Sm), Cornus florida (Cf), Liriodendron tulipifera (Lt) and Quercus serrata (Qs). Carbo-oxylation efficiency and photon yield of Sp decreased on 40ﾟC.Stomatal conductance of Cf and Lt was suppressed and recovered after treatment. The effect was seldom observed on Qs. Due to complex effect of heat and water stress, the photosynthetic processes of Sm and Cf were inhibited under the more mild condition than single stress. 2.Heat effects on reproductive organ Treatment of high temperature 40ﾟC did not affected the vegetative growth of Capsicum frutescens, but decreased the reproductive growth. The mechanism of the effects on reproductive organ was studied through the analysis of assimilation and allocation. 3.Mathematical model on drought injury The model was composed of the sub-models of evapo-transpiration, water uptake, changes of soil moisture and heat budget of leaf. The injury was assumed to be caused by leaf temperature and dehydration. On the assumption of the physiological parameters of Populus alba, heat injury was caused on the higher air temperature than 38ﾟC.If LAI of stand of Populus alba is 6 and available soil thickness is 50cm, drought damage was caused after 2 weeks of rainless period. 4.Stress-monitoring The method of stress-monitoring of trees was studied for the use of the high-resolution satellite data. The treatment of water- and heat-stress shifted the red edge of Sp 15nm to the side of short wave region. The increase of stress index was correlated to the decrease of photosynthetic rate and stomatal conductance.