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Photosynthetic Response to Seawater Flooding Stress of Hibiscus Hamabo Sieb.et Zucc.and Myrica Cerifera

Author: WangZongXing
Tutor: YuMuKui
School: Chinese Academy of Forestry
Course: Forest cultivation
Keywords: Hibiscus Bayberry wax Seawater Stress Photosynthetic physiology
CLC: S685.99
Type: Master's thesis
Year: 2011
Downloads: 28
Quote: 1
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Abstract

In this study, the Hangzhou Bay Wetland Ecosystem Research Station platform Hibiscus (Hibiscus hamabo Sieb.et Zucc.) And wax bayberry (Myrica cerifera) for the study, stress test by simulating different levels of seawater, continuous determination of the two of different plant species characteristics, physiological growth and morphological structure, designed to explore two plants to Seawater Stress of photosynthetic physiological response mechanism and differences provide a theoretical basis for the the wave dissipation plant build. The results show that: the two plants affected by coastal flooding stress, changes of photosynthetic characteristics consistency, net photosynthetic rate (Pn) with prolonged flooding time performance of a gradual downward trend. Also found that seawater stress affect the the Hibiscus afternoon photosynthetic rate of recovery, and the impact of seawater stress on the wax Yang Meiguang peak of. By analyzing the reason for the change of two plant photosynthetic rate in seawater stress conditions, the conclusions are as follows: (1) in the process of photosynthesis, Pn and photosynthetic factor Path analysis results show that under seawater stress transpiration rate (Tr) , intercellular CO2 concentration (Ci) are affecting the direct factor of two plants Pn seawater stress under Tr, the size of Ci direct impact on plant photosynthetic characteristics. Hibiscus daily flooding Time 2h flooded to a depth of 15cm processing and flooding time 4h, water flooded the the depth 25cm processing directly impact factor for TR and PAR (intensity), a deeper degree of flooding flooding time 6h, flooding depth of 35cm processing and flooding time 8h flooded the depth 45cm processing directly impact factor becomes Cond (stomatal conductance), Ci, bayberry wax daily flooded time 2h, flooding the depth of 15cm processing and flooded time 4h, flooding the depth 25cm processing directly impact factor of Tr, Cond, deeper flooding flooding time 6h flooded to a depth of 35cm processing and flooding time 8h, flooding depth 45cm process directly affect the factor becomes Ci VPD (vapor pressure deficit values). (2) in photosynthetic pigments, waterfront Hibiscus chlorophyll a / b initial stage first increases and then decreases, a growing trend of late, faster decomposition of chlorophyll b, and plant faster degradation of light-harvesting pigment-protein complex after flooding, slow degradation of the optical system reaction center, that affected by the flooding, the plant by adjusting the ratio of leaf chlorophyll a and chlorophyll b to sustain its high photosynthetic capacity; wax bayberry chlorophyll a / b showing a downward trend after the first increase, indicating The initial light-harvesting pigment-protein complex degradation late light reaction centers of rapid degradation. (3) in respiratory energy consumption, plant photosynthesis reduce the lead to a lot of excess energy by photorespiration and chlorophyll fluorescence to eliminate. The Hibiscus and wax bayberry moderate stress, glycolic acid oxidase activity maximum, photorespiration, the ability to reduce glare hazards, flooding deeper, glycolic acid oxidase activity significantly reduce photorespiration resist stress The ability decreases. Chlorophyll fluorescence observation found that the rise of non-photochemical quenching (qN or NPQ) caused by heat dissipation. Under seawater stress excess light energy dissipation by non-photochemical quenching. (4) in osmotic adjustment, flooded environment wax bayberry more proactive accumulation of soluble sugar, saving energy, regulating the osmotic pressure in order to resist the stress environment, but Hibiscus leaf starch content in general showed a gradual increase throughout the test period trend, while bayberry wax processing L4 had already appeared a sharp drop of the starch content, bayberry wax soluble protein content than the Hibiscus in advance downward inflection point. In osmotic adjustment Flooding Stress capacity Hibiscus better than bayberry wax. Found by observation under seawater stress Hibiscus and bayberry wax morphological index seawater stress the deeper level of flooding the longer the more serious degree of leaf yellowing, plant height growth, root growth more suppressed. But at the same time under seawater stress Hibiscus adventitious root growth, promote lateral growth of the the stem lenticels increases and plant stems the plant ground diameter was significantly higher than that of the control. Seawater stress under Hibiscus also has strong sprouting ability, H6 treatment Hibiscus twig significantly increased the number was significantly higher than that of the control and other treatments. Wax bayberry no adventitious roots, twigs growth in the number, height, diameter with flooding time and the degree of flooding deepening gradually decreased. Through the observation of morphological index, we can determine Hibiscus over wax bayberry anti-flooding capacity.

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