The Comparising Research On Chlorophy Ⅱ Fluorescence Characteristics And Growth Of Five Evergreen Broad-leaved Seedlings Under The Stress Of Acid Rain, UV-B And Light Stress

As the global change, rapid economic growth subtropical regions, increased acid rain pollution, atmospheric ozone layer, becoming thinner, ultraviolet radiation has gradually increased burning of fossil fuels, aerosol and cloud brightness enhancement, parasol effect of worsening greatly changed the environment for plant life. Therefore, by studying the acid rain, UV-B and light intensity on the subtropical evergreen broad-leaved forest seedlings of different species, For in-depth understanding of global change (increase acid rain, UV-B radiation increased and decreased intensity) on the subtropical evergreen broad-leaved forest forest update, community dynamics and succession and the recovery of great significance.In this study, the main tree species in subtropical evergreen broad-leaved forest: Castanopsis(Castanopsis sclerophylla), Schima(Schima superba), camphor (Cinnamomum camphora), Lithocarpus (Lithocarpus glaber) and Elaeocarpaceae (Elaeocarpus decipiens) of five tree species experimental materials, use of ecological simulation methods, using self-control facilities, set severe acid rain (pH2.5), moderate acid (pH4.0) and control (pH5.6) three kinds of acid rain; Enhanced UV-B group (compared with the control group increased 10% UV-B), UV-B filter group (control group of about 20% of UV-B) and control group (daylight conditions) of three UV-B treatment;and 100%, 75% and 50% of the three kinds of light intensity, measured relative chlorophyll content, chlorophyll fluorescence parameters and growth (height and diameter) and other parameters, 5 species of seedling growth and physiological parameters such as chlorophyll fluorescence effects.The results show that: (1) Sylvestrial acid conditions can be very heavy growth of Schima superba, Cinnamomum camphora and Castanopsis, under the conditions of the medium is more suitable for the growth of acid rain, stone oak in the absence of acid or slightly acid conditions can be more good growth. The acid conditions, Elaeocarpus sylvestris seedlings and chlorophyll fluorescence parameters of chlorophyll (Fv/Fm, Fv/Fo andΦPSII) With the increase of acid concentration, qN increased with the concentration of reducing acid rain; Schima superba, Cinnamomum camphora, Castanopsis and Lithocarpus acid concentration increased with chlorophyll content and fluorescence parameters (Fv/Fm, F/Fo andΦPSII) has decreased.(2) Enhanced UV-B radiation can promote Schima and Elaeocarpus, restrained Cinnamomum, Castanopsis and Lithocarpus seedling growth; reduced UV-B radiation for Cinnamomum, Castanopsis and Lithocarpus seedling growth. Enhanced UV-B radiation reduced the Elaeocarpus glaber and chlorophyll content of seedlings and some pigment fluorescence (Fv / Fm, Fv / Fo andΦPSII), but on Schima superba, Castanopsis camphor and little effect on the chlorophyll content of seedlings However, some chlorophyll fluorescence parameters of a certain inhibition (Fv / Fm, Fv / Fo andΦPSII).(3) In 50% of all light conditions of Schima superba, Castanopsis and Lithocarpus seedling growth was inhibited, while promoting the growth of seedlings Elaeocarpaceae and camphor. 5 kinds of subtropical evergreen broad-leaved seedlings in the chlorophyll content, Fv/Fm, Fv/Fm andΦPSII in low light were significantly higher than under all light conditions, tree seedlings are suitable for low Light performance.(4) Three months through spring and autumn and the determination of acid rain, UV-B and light treatment on the five kinds of subtropical evergreen broadleaved seedlings have a good season, chlorophyll content changes: May