This study was conducted to figure out the differences in physiological responses, e.g. growth, photosynthetic activity and water potential, and photoinhibition tolerance in photosystem between superior and inferior families of Pinus densiflora under drought condition. Superior which is KW85 and inferior which is KW40 families were selected using progeny test results of height growth. In 2007, seeds were collected from seed orchard. In 2008, seedlings were produced and cultivated, and from April 2009 drought treatment was started with shading treatment and plants were harvested in Sept. 2009. There was no significant difference in height growth between families. In case of leaf water potential, KW85 showed higher water potential under drought condition. But there was no significant difference in drought with shading treatment. There was no difference in photosynthetic rate but stomatal conductance and transpiration rate of KW85 showed lower value than KW40. So water use efficiency of KW85 showed higher value in every treatment. Non-photochemical quenching of KW40 showed higher value in drought treatment, but there was no significant difference in control and drought with shading treatment. Xanthophyll cycle pool size of KW85 showed higher value in drought treatment, but in drought with shading treatment KW40 showed higher value. Selected superior family showed higher drought tolerance according to water use efficiency, and it also has effective non-photochemical quenching ability. In contrast inferior family respond more sensitively in photoinhibition under drought condition.

Genetic Analysis of Photoinhibition in Barley

이식후 생육초기의 잎담배 (품종 :Bulgaria)와 3연근 인삼을 공시하여 광강도를 580, 1,280, 1,770, 2,580 u E/m2 /sec로 각각 3,6,9시간을 엽온 22℃ 의 조건에서 처리한 후 CO2 농도 320ppm에서 광일광합성속도를 조사하였다. 1. 처리전 인삼의 광포화점은 어느 온도 조건에서나 공히 550u E/m2 /sec 정도였고, 광합성속도는 20℃ 에서 7.2, 35℃ 에서 5.2mg.CO2 /dm2 /hr이었다. 잎담배는 광포화점이 25℃ 에서 1,600u E/m2 /sec에서 나타났고, 광합성속도는 25℃ 에서 14.3, 15℃ 에서는 10.3mg.CO2 /dm2 /hr이었다. 2. 잎담배는 어느 처리에서나 광저해가 일어나지 않았다. 3. 인삼은 3시간 처리에서는 2,580u E/m2 /sec의 광도에서만 광합성속도가 11.4% 저하되었고, 9시간 처리에서는 1,270u E/m2 /sec 광도에서 8.5%, 1,770u E/m2 /sec에서 9.5%, 2,580u E/m2 /sec에서 20.3%로 각각 저하되어 광강도가 크고 조사기간이 길수록 광저해가 컸다. 4. 인삼에서 기공저항은 처리간에 차이가 없었으나, 엽육저항은 광저해를 받은 처리에서 크게 나타냈고. 담배에서는 처리간에 차이가 인정되지 않았다.