关键词: 狗牙根, 脱水, 光合机构, 快速叶绿素荧光

Abstract:

Bermudagrass (Cynodon dactylon L.), as wildly used turfgrass, is often subjected to extreme drought stress resulting in dehydration of leaves. In this paper, the effects of dehydration stress on the photochemical activities of photosystems including photosynthetic system 2 (PSⅡ) and photosystem 1 (PSI) of bermudagrass leaf were studied using fast chlorophyll fluorescence transient and 820 nm light absorption technology. The results showed that dehydration in the dark degraded the leaf chlorophyll and severely damaged the photochemical activity of the photosynthetic apparatus. With the exacerbation of dehydration, the activity of PSI and PSⅡ decreased gradually and significantly. The decrease of PSI activity (ΔI/Io) was earlier and more serious than the decrease of PSⅡ (Fv/F and Ψo). It demonstrated that the PSI activity was more sensitive to dehydration than PSⅡ activity. The photosynthetic performance index based on light energy absorption basis (PI_ABS) accurately and sensitively reflected the response of photosynthetic electron transport chain leaf between two photosystems of Cynodon dactylon L. to dehydration in the dark, and could be used as a rapid and effective index for cultivation and identification of drought tolerance varieties of bermudagrass.

Key words: Cynodon dactylon L., Dehydration, Photosynthesis apparatus, Chlorophyll a fluorescence transient