紅海欖苗木於不同鹽度處理下光合作用光保護機制之探討

A STUDY ON PHOTOPROTECTION MECHANISM OF PHOTOSYNTHESIS IN RHIZOPHORA STYLOSA SEEDLINGS UNDER DIFFERENT SALINITY TREATMENTS

王經文(Ching-Wen Wang) ； 廖天賜(Tien- Szu Liao) ； 翁韶良(Shau-Lian Wong) ； 陳明男(Ming-Nan Chen) ； 陳忠義(Chung-I Chen)

《中華林學季刊》 53卷1期 (2020/03) Pp. 33-54

摘要

本研究以紅海欖（Rhizophora stylosa Griff.）苗木為對象，使用5種鹽度處理9個月後，量測其氣體交換與葉綠素螢光參數，探討其光合作用之光保護特性。結果顯示紅海欖在（千分之10）－（千分之20）鹽度範圍內有較佳之光合生理反應，其光誘導特性在光照初期30 min內，光合作用速率與氣孔導度皆低，此時段葉片天線系統所吸收之輻射能量以非光化學消散為主要路徑，屬非氣孔性因素；當光照持續到30-90 min時，光合作用速率才逐步提升，此時氣孔開度亦同步提升，吸收之能量仍以非光化學消散為主，屬氣孔因素。在低光源（0-400μmol photon m^(-2) s^(-1)）時，以非光化學消散之光保護為主，待光量達800-2,000 μmol photon m^(-2) s^(-1)階段時，在光合作用提高的同時，仍以非光化學消散及熱消散來保護光合系統。結論，紅海欖之光保護機制是為適應生長環境鹽度與光度動態變化，發展出不同階段能量利用的光合生理行為。

關鍵字

氣體交換 ； 非光化學消散 ； 光誘導 ； 光保護 ； 鹽度

並列摘要

Photoprotection characteristic of photosynthesis were evaluated for Rhizophora stylosa seedlings under five salt gradients treatments in this study. The results showed that R. stylosa was suitable for growing in the salinity range of (10 per mille)-(20 per mille). The photoinductive characteristic of the R. stylosa seedlings were affected by the irradiation intensity and duration. In the first 30 minutes of irradiation, the photosynthesis rate was almost unactivated, and the stomata closed too. The energy absorbed by leaves in this period is mainly quenched by non-photochemical quenching. This stage was affected by non-stomatal factor. When the irradiation lasted for 30-90 minutes, the photosynthesis rate gradually increased. At this time, the stomata open synchronously. The absorbed energy was still affected mainly by non-photochemical quenching, which was affected by stomatal factor. At low irradiation (0-400 μmol photon m^(-2) s^(-1)), the photosynthetic physiological behavior of R. stylosa was photoprotection dominated by non-photochemical quenching. When the light intensity reached 800-2,000 μmol photon m^(-2) s^(-1), the energy absorbed was processed mainly by non-photochemical quenching and heat quenching. When the photosynthetic system was protected, photosynthesis was further improved. The photoinductive mechanism of R. stylosa has adapted to the dynamic changes of salinity and irradiation in the growth environment, and developed photosynthetic physiological behaviors at different stages of energy utilization and photoprotection.

並列關鍵字

Gas exchange ； Non photochemical quenching ； Photoinduction ； Photoprotection ； Salinity