乾旱逆境下亞托敏及硒處理對茶樹 (Camellia sinensis) 葉片生理之影響

The Effects of Azoxytrobin and Selenium on the Physiology of Tea (Camellia sinensis) Leaves under Drought Stress

邱昱潔(Yu-Chieh Chiu)

指導教授 ： 黃文達

國立臺灣大學/生物資源暨農學院/農藝學研究所/碩士(2020年)

https://doi.org/10.6342/NTU202003225

摘要

茶樹 (Camellia sinensis) 是臺灣重要的飲料作物，現行茶樹栽培大多是看天田，在非雨季時常遭遇乾旱而降低茶樹產量及製茶品質。在乾旱時，茶農會以植生覆蓋、敷蓋或淺耕土表等田間操作的方式來減少土壤水分的蒸發。前人研究指出，在乾旱時，施用亞托敏或硒可以幫助植物維持滲透壓、光合作用及增加抗氧化酶的活性，進而減緩乾旱對植物造成的生理傷害。由於目前茶園遭遇乾旱，農民所採用的田間操作無法從生理方面提升茶樹的耐旱性，因此本文主要探討乾旱對茶樹造成的生理傷害是否能被外加的亞托敏或硒緩解。本試驗採小葉種茶樹臺茶12號（金萱）展開葉切離之直徑 1.2 公分的葉圓片，以四種濃度 (0、22.8、33.2、41.1 %) 的聚乙二醇 (PEG-6000) 溶液做滲透處理模擬乾旱逆境；另比較於 0、22.8 % PEG 處理前，預措亞托敏（0.125 g L-1 和 1.25 g L-1）與亞硒酸鈉（1 mg L-1 和 5 mg L-1）之效果。實驗結果顯示 PEG 誘導的乾旱逆境會降低茶樹葉圓片的光合系統 PS II 的效率、色素含量和抗氧化能力，提高膜的過氧化程度；在模擬乾旱逆境下，亞托敏和硒處理對葉綠素螢光指標影響不一致，但會降低丙二醛及類胡蘿蔔素的含量，亞托敏處理可以提高抗氧化能力指標，但卻降低了光合色素含量。亞托敏和硒處理可以降低模擬乾旱逆境對茶樹葉圓片的過氧化傷害，但其中機制還需再做研究。本實驗提供了一個快速評估外加處理對改善茶樹乾旱逆境傷害的方法。

關鍵字

茶樹 ； 葉圓片 ； 滲透壓逆境 ； 亞托敏 ； 硒 ； 葉綠素螢光

並列摘要

Tea plant (Camellia sinensis) is an important beverage crop in Taiwan, which is usually grown under rain-fed cultivation. Therefore, drought is major abiotic stress which reduces tea yield and product quality, especially in the non-rainy season. Tea farmers nowadays cover the soil surfaces with plant materials or shallow plowing to reduce soil evaporation. Several studies revealed that exogenous azoxystrobin and selenium enhances drought tolerance by maintaining osmotic pressure, photosynthesis, and improving antioxidant enzyme activity in other plant species. Current field managements for tea plants under drought stress are not effective on the physiological level. Therefore, we aimed to understand the alleviating effects of azoxystrobin and selenium on tea plant physiological damage under drought. Expanded leaves of Taiwan Tea Experiment Station No. 12 (Jin-Xuan) were cut into leaf discs with a diameter of 1.2 cm. Polyethylene glycol (PEG-6000) whose concentration is 0, 22.8, 33.2, and 41.1 % were used to induce drought for leaf discs in petri dishes and the osmotic potential is 0, -0.6, -1.2 and -1.8 MPa, respectively. 22.8 % PEG was chosen as drought-induced concentration, pre-treated by 0.125 and 1.25 g L-1 azoxystrobin or 1 and 5 mg L-1 sodium selenite. The results revealed that tea leaf discs decreased maximum PSII efficiency, photosynthetic pigment content, and antioxidant capacity, however, increased lipid membrane peroxidation under osmotic-induced drought stress. Azoxystrobin and selenium treatment under 22.8 % PEG have an inconsistent response on chlorophyll fluorescence parameters but decrease malondialdehyde and carotenoid content. Azoxystrobin treatment under 22.8 % PEG would increase antioxidant capacity but decrease photosynthetic pigment content. Although the effects of azoxystrobin and selenium are little, our work represented a rapid method for assessment of exogenous treatment alleviating effect on tea drought damage.

並列關鍵字

Camellia sinensis ； leaf discs ； osmotic stress ； azoxystrobin ； selenium ； chlorophyll fluorescence

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