식물의 광합성에 관여하는 광계 I의 protein subunit들의 연구는 최근까지도 극히 미약한 실정이며, 각각의 subunit들의 특성 또한 일부만이 밝혀져 있다. 본 연구진은 배추의 cDNA library로부터 식물에만 존재하는 subunit 중의 하나인, PSI-H subunit을 암호화하는 유전자인 bpsaH를 분리하였다. 이 유전자는 총 633 bp의 염기로 구성되어 있으며, 염기서열로부터 추정되는 분자량은 약 15,400이었고 등전점은 9.

In this study, we analyzed the relationships between weather factors and photosystem II activity (Fv/Fm), as a measure of photochemical efficiency, in three cool-season turfgrasses commonly planted on golf courses in Jeju, South Korea: perennial ryegrass (Lolium perenne L.), Kentucky bluegrass (Poa pratensis L.), and creeping bentgrass (Agrostis palustris Huds.). In all three turfgrasses, Fv/Fm was higher during late summer than during early summer. However, in late summer, Fv/Fm was significantly lower in perennial ryegrass than in the other two species. In early summer, Fv/Fm in perennial ryegrass and Kentucky bluegrass was positively correlated with mean low temperature and extreme minimum temperature, whereas, in late summer, this parameter in Kentucky bluegrass and creeping bentgrass was positively correlated with relative humidity, and in creeping bentgrass was negatively correlated with mean high temperature, mean low temperature, and extreme maximum temperature. These results indicate that raising low temperatures is favorable for perennial ryegrass and Kentucky bluegrass in early summer, whereas, in late summer, the lowering of high temperatures proves to be beneficial for creeping bentgrass, and raising relative humidity is conducive to the growth of Kentucky bluegrass and creeping bentgrass. These findings will contribute to improving the selection and management of turfgrasses on golf courses and sports fields.

This study was performed to investigate the physiological responses of Oplopanax elatus by water condition.Drought stress was induced by withholding water for 26 days. The results show that PN max, SPAD, gs, E and Ci weresignificantly decreased with decreasing of soil moisture contents. However, AQY and WUE were decreased slightly only at26 day. This implies that photosynthetic rate is reduced due to an inability to regulate water and CO₂exchange through thestomatal. According to JIP analysis, ΦPO, ΨO, ΦEO and PIABS were dramatically decreased at 21 day and 26 day, whichreflects the relative reduction state of the photosystem II. On the other hand, the relative activities per reaction center suchas ABS/RC, TRo/RC were significantly increased at 26 day. Particularly, Dio/RC and DIo/CS increased substantially underdrought stress, indicating that excessive energy was consumed by heat dissipation. These results of chlorophyll a fluores-cence show that the sensitivity changes photosystem II activity. Thus, according to the results, O. elatus was exhibited astrong reduction of photosynthetic activity to approximately 10% soil moisture contents, and JIP parameters could be usefulindicator to monitor the physiological states of O. elatus under drought stress.