調缺灌溉及添加生物刺激劑對‘福山’萵苣及‘華珍’玉米生長之影響

Abstract

本研究以‘福山’萵苣(Lactuca sativa ‘Fu San’)及‘華珍’玉米 (Zea mays ‘Hua Chen’)作為材料進行調缺灌溉(Regulated deficit irrigation, RDI)以及在調缺灌溉下添加幾丁質(chitin)和殼聚糖(chitosan) ，評估其對植株生長和節水效益之影響。 在‘福山’萵苣調缺灌溉試驗方面，將‘福山’萵苣分為兩期，7-12片葉為前期，12-18片葉為後期，各別進行輕度缺水及中度缺水。‘華珍’玉米調缺灌溉試驗為將玉米分為營養生長期及生殖生長期，各別進行缺水處理。另外，‘福山’萵苣及‘華珍’玉米在調缺灌溉下添加2000 mg·L-1幾丁質、200 mg·L-1及400 mg·L-1藥用殼聚糖以及200 mg·L-1及400 mg·L-1商用殼聚糖(金甲讚)。 結果顯示：在夏季‘福山’萵苣前期輕度缺水及中度缺水處理後產量與對照組相比沒有減少，而且可以提高經濟產量水分利用效率(yield water-use efficiency, WUEyield) 及生物產量水分利用效率(biomass water-use efficiency, WUEbiomass)，因此可以節省2.63%及21.05%的灌溉水量。在冬季‘福山’萵苣調缺灌溉處理組間皆無顯著差異，其中以後期中度缺水WUEyield 及WUEbiomass最高，可以節省28.63%的灌溉水量。玉米調缺灌溉處理後與對照組生長表現沒有顯著差異，但生殖生長期缺水處理WUEyield 及WUEbiomass最高，能節省40.10%的灌溉水量，其次為營養生長期缺水處理WUEyield 及WUEbiomass，能節省22.70%的灌溉水量。 在調缺灌溉下添加幾丁質及殼聚糖試驗結果顯示：‘福山’萵苣在鮮重及WUEyield方面，雖然調缺灌溉添加200 mg·L-1及400 mg·L-1藥用殼聚糖及金甲讚處理與調缺灌溉處理生長表現統計沒有顯著差異，但調缺灌溉添加200 mg·L-1殼聚糖及金甲讚處理有略佳的趨勢。調缺灌溉添加200 mg·L-1殼聚糖處理在乾重、株高、根長、葉片數、葉面積及WUEbiomass表現皆有較調缺灌溉添加2000 mg·L-1幾丁質處理及調缺灌溉添加200 mg·L-1金甲讚處理佳的趨勢。因此在調缺灌溉添加2000 mg·L-1幾丁質處理、調缺灌溉添加200 mg·L-1殼聚糖處理及金甲讚處理間，綜合表現較佳的為調缺灌溉添加200 mg·L-1殼聚糖處理。‘華珍’玉米鮮重、乾重、株高在調缺灌溉添加200 mg·L-1及400 mg·L-1藥用殼聚糖及金甲讚處理與調缺灌溉處理沒有顯著差異，但以經濟成本而言調缺灌溉添加200 mg·L-1殼聚糖及金甲讚處理會較佳。‘華珍’玉米在調缺灌溉添加2000 mg·L-1幾丁質處理、調缺灌溉添加200 mg·L-1殼聚糖及金甲讚處理的鮮重、乾重及株高皆與調缺灌溉處理生長表現統計沒有顯著差異。 雖然‘福山’萵苣於夏季進行調缺灌溉對提升作物水分利用效率較冬季顯著。冬季‘福山’萵苣及玉米調缺灌溉處理與對照組沒有顯著差異，表示在冬季‘福山’萵苣對缺水的敏感度下降，進而可以節省更多的水；另推測玉米為較耐乾旱作物，未來可以嘗試增加缺水強度，以節省更多的水，達到精準農業。本試驗結果雖顯示幾丁質或殼聚糖對‘福山’萵苣及‘華珍’玉米沒有顯著的節水效果，但品嚐口感較佳，推測幾丁質或殼聚糖可能會增加‘福山’萵苣及‘華珍’玉米的總可溶性之固形物，因此有待進一步深入探討。

In this study, lettuce (Lactuca sativa ‘Fu San’) and corn (Zea mays 'Hua Chen') were used as materials for regulated deficit irrigation (RDI) and chitin and chitosan was added under regulated irrigation, evaluated for their effects on plant growth and water-saving benefits. In the lettuce RDI experiment, the lettuce was divided into two phases, 7-12 leaves were in the early stage, and 12-18 leaves were in the late stage, with mild and moderate water deficit. In the corn RDI experiment, the corn was divided into vegetative stage and reproductive stage with water deficit. In addition, in the lettuce and corn supplemented experiment, lettuce and corn were supplemented with 2000 mg·L-1 chitin, 200 mg·L-1 and 400 mg·L-1 medicinal chitosan and commercial chitosan (JinJiaZan) under water deficit. The results showed that the yield of the mild and moderate water deficit treatment in the early stage of lettuce in summer was not reduced compared with the control group, and the yield water-use efficiency (WUEyield) and the biomass water-use efficiency (WUEbiomass) could be improved, thus saving 2.63% and 21.05% of the irrigation water. There was no significant difference in the treatment of lettuce in the winter. In the later stage, the moderate water deficit WUEyield and WUEbiomass, which could saved 28.63% of the irrigation water. There was no significant difference in growth between the control and the RDI treatment of corn, but reproductive stage water deficit were the highest WUEyield and WUEbiomass, which could save 40.10% of irrigation water, followed by the vegetative stage water deficit, which can save 22.70% of irrigation water. The results of the experiment of addition chitin and chitosan indicated (medicinal chitosan and commercial chitosan) under water deficit that lettuce was added with 200 mg·L-1 and 400 mg·L-1 medicinal chitosan and JinJiaZan in the treatment of fresh weight and WUEyield was no significant difference in the RDI treatment, but there was a better trend in the treatment of 200 mg·L-1 chitosan and Jinjiazan. The RDI addition of 200 mg·L-1 chitosan treatment of dry weight, plant height, root length, leaf number, leaf area and WUEbiomass were better trend then the treatment of RDI addition 2000 mg·L-1 chitin and RDI addition of 200 mg·L-1 JinJiaZan. Fresh weight, dry weight and plant height of corn were not significantly different between the treatment of RDI addition 200 mg·L-1 and 400 mg·L-1 chitosan and JinJiaZan treatment, but consider the economic efficiency RDI addition 200 mg·L-1 treatment is better. After that, the fresh weight, dry weight and plant height of corn treated with RDI addition 2000 mg·L-1 chitin and RDI addition 200 mg·L-1 chitosan and JinJiaZan were no significant differences in growth statistics. Although the lettuce was used to adjust the water use efficiency in the summer to improve the water use efficiency of crops compared with winter. There was no significant difference in the winter lettuce and corn RDI treatment test, indicating that the sensitivity of lettuce to water deficit in winter decreased, which in turn could save more water, and it was also speculated that corn was more resistant to drought. In the future, we can try to increase the water deficit intensity to save more water and achieve precision agriculture. Although the results of this test showed that chitin or chitosan lettuce and corn did not have significant by water saving effect on lettuce and corn, but the taste is better, it is speculated that chitin or chitosan may increase the total soluble solids of lettuce and corn, so it needs further exploration.