Photosynthetic responses and photoprotection in Korean hot pepper (Capsicum annuum L.) against high light stress = 광 스트레스에 대한 고추 잎의 광합성 반응과 광 보호 메커니즘

Abstract

Photoinhibition and photoprotection of PSII in the leaves of hot pepper (Capsicum annuum L.) grown in Hoagland solution and Tap water were compared. Though changes in the rates of O2 evolution as a function of photon fluence rate (PFR) were comparable, the rates of respiration in the dark was 3 times higher in the Hoagland solution grown leaves than in the Tap-water grown ones. Compared to Hoagland solution grown plants, PSIIs of Tap water grown pepper leaves were more susceptible to photoinhibitory light treatment. In order to inactivate functional PSII to the same extents, Hoagland solution grown plants required almost 2-fold high light (1600 μmolm-2s-) treatment than those of Tap water (900 μmolm-2s-1). Interestingly, the remaining fraction of PSII in Hoagland grown pepper was able to survive under prolonged illumination in the presence of lincomycin, which probably means that the growth condition of plant seemed to have an effect on the recovery of PSII from light stress. When PSII was severly photoinactivated at a chilling temperature, recovery was observed only if the residual functional PSII were not inhibited with DCMU, Nigericin and MV during recovery. In conclusion, PSIIs grown in the Hoagland solution was more resistant to excess light than in the Tap water grown one and the recovery of PSII from photodamage was more efficient in Hoagland grown pepper leaves than Tap water grown one, which means that the increased dark respiration may play a important role in the protection of PSII from photoinhibition by helping repair photosynthetic proteins (in particular, the D1 protein of PSII) degraded by photoinhibition.