| Effect of regulated deficit irrigation on photosynthetic characteristics of Capsicum annum in dry oasis environment |
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| DOI：10.7606/j.issn.1000-7601.2013.04.021 |
| Key Words: deficit irrigation Capsicum annuum gas exchange chlorophyll fluorescence parameters |
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| Abstract: |
| Three deficit irrigation treatments (light, moderate and severe deficit irrigation) and normal irrigation as control were tested on Meiguohong (dried variety of Capsicum annuum) in the field of dry oasis in the lower reaches of Shiyanghe River in attempt to investigate the effects of
deficit regulated irrigation (RDI) on gas exchange and chlorophyll fluorescence characteristics at flourishing stage of Capsicum annuum, and to provide some theoretical reference for water management of Capsicum annuum. The results showed that the diurnal variation curves of net photosynthetic rate (Pn) and transpiration rate (Tr) demonstrated two-peak and one-peak curve respectively under normal irrigation (CK) and light regulated deficit irrigation (LD), and showed one-peak curve under moderate regulated deficit irrigation (MD) and severe deficit irrigation (SD). RDI significantly reduced Pn, Tr and stomatal conductance(Gs). With the increase of water deficit, the non-stomatal limitation of photosynthesis appeared earlier and prolonged, causing significant reduction in water use efficiency. The effect of LD on the content of photosynthetic pigment and chlorophyll fluorescence parameters was not significant. Under MD treatment, the content of chlorophyll decreased significantly, but the content of carotenoid had not obvious decrease. Potential activity of PSⅡ and quantum yield of PSⅡ decreased significantly, indicating remarkable inhibition in photochemical activity of PSⅡ; The maximum photochemical efficiency of PSⅡ and electric transport rate had no obvious change but non-photochemical quenching increased noticeablely, which indicated that heat dissipation played important role in the protection of photosynthetic apparatus. The effects of SD on photosynthetic pigment content, gas exchange and chlorophyll fluorescence parameters were significant, and the PSⅡsystem was severely damaged. The LD treatment had no significant affect on photosystem II, but improved WUE and substantially decreasedTr than Pn, which may lead to the improvement of water use efficiency. |
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