狼尾草耐旱性生理指標之研究

本研究以狼尾草台畜草三、六、七、八號（Napiergrass Taishiu cv. No. 3、6、7、8）作為試驗材料，於可遮雨之網室內進行試驗。試驗之對照組每週澆水施灌2次，處理組每2週澆水施灌1次，模擬牧草生長期遭遇乾旱逆境之狀況。試驗結果顯示，所有品種狼尾草之鮮重產量，處理組皆顯著低於對照組。狼尾草三、七、八號之處理組SPAD值（Soil-Plant Analysis Development value）顯著低於對照組，電解質滲漏率方面，所有品種之處理組皆顯著高於對照組。水溶性碳水化合物含量及澱粉含量方面則為所有品種狼尾草在處理之間並未有顯著差異。無機離子方面，狼尾草台畜草三號處理組之鈣離子含量顯著高於對照組。將上述等生理指標與鮮重產量作相關性分析，其結果顯示SPAD值及電解質滲漏率與鮮重產量之相關係數最高，其相關係數皆大於0.7，屬高度相關，因此SPAD值及電解質滲漏率適合作為篩選指標評估狼尾草之耐旱性。

關鍵字

狼尾草；耐旱性；生理指標；芻料作物

並列摘要

In this study, Napiergrass Taishiu cv. No. 3, 6, 7, 8 (NP cv. TS 3, 6, 7, 8) were cultivated in the pot with different water condition under shading-nets to determine the agronomic traits and physiological values. In the trial, the control treatment was irrigated twice a week, and the drought treatment groups were irrigated once every two weeks, in simulation of the drought adversaries during the growth period of grass. The results showed that the fresh biomass yields of all napiergrass varieties were significantly lower in the drought groups than those in the control group. The SPAD (Soil-Plant Analysis Development) values of NP cv. TS 3, 6, and 8 were significantly lower in the drought groups. In terms of electrolyte leakage rate, the drought groups of all napiergrass varieties were significantly higher than the control group. There were no significant differences between control groups and drought groups in the water-soluble carbohydrate contents and the starch contents of all the varieties. With regards to the inorganic ions, the content of Ca^(2+) in the drought group of NP cv. TS 3 was significantly higher than that in the control group. Correlation analyses showed that the correlation coefficients between fresh yield and SPAD value, and between fresh yield and electrolyte leakage rate were the highest, which correlation coefficient was greater than 0.7 and highly correlated. Hence, findings suggest that SPAD value and electrolyte leakage rate might be used as the physiological index for evaluating the drought tolerance of napiergrass.

並列關鍵字

Napiergrass ； Drought tolerance ； Physiological index ； Forage crops

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