Photosynthetic and physiological responses of native and exotic tidal woody seedlings to simulated tidal immersion
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- 作者：Tonggui Wu ; Shenhua Gu ; Hefeng Zhou ; G. Geoff Wang ; Xiangrong Cheng ; Mukui Yu
- 关键词：Hibiscus hamabo ; Myrica cerifera ; Tidal effect ; Photosynthesis ; Plant physiology ; Hydrothermal solutions
- 刊名：Estuarine, Coastal and Shelf Science
- 出版年：20 December, 2013
- 年：2013
- 卷：135
- 期：Complete
- 页码：280-284
- 全文大小：682 K
文摘
Hibiscus hamabo, a native tidal woody species, and Myrica cerifera, an exotic tidal woody species, have been widely planted on coastal beaches in subtropical China. However, whether there are differences in physiological response and tolerance to immersion between the two tidal species is still unknown. Our objectives were to evaluate differences in the photosynthetic and physiological responses to tidal immersion for the two species in the context of sea level rise. With increasing immersion, net photosynthesis, stomatal conductance, intercellular CO2 concentration, and light saturation point declined progressively for both species, whereas dark respiration and light compensation point showed the reverse trend. Lower variation was observed in H.聽hamabo than in M.聽cerifera for each index in the same treatment. Photosynthetic ability and utilization of light, especially under high light intensity, decreased for both species. Leaf soluble sugar and protein contents, and glycolate oxidase activity first increased and then decreased with increasing of immersion degree, with the higher values observed in the W4 (4聽h duration, 15聽cm depth) and W6 (6聽h duration, 25聽cm depth) treatments for H.聽hamabo, and W2 (2聽h duration, 5聽cm depth) and W4 treatments for M.聽cerifera. These findings indicate that H.聽hamabo has a better ability to keep the reduction of photosynthesis at a minimum through soluble substance regulated osmotic potential and avoiding excess light damage to the photosynthetic system through increased photorespiration, heat dissipation, chlorophyll fluorescence. Our results suggest that H.聽hamabo is more tolerant to tidal immersion than M.聽cerifera, and therefore it is better adapted to the anticipated sea level rise in future.