Y.C. Lai1,* J.L. Hwang1 Hsiao F. Lo2 Kuan H. Lin3
1Chiayi AES, ARI, COA, Executive Yuan
2National Taiwan University
3Chinese Culture University
*corresponding author, E-mail: [email protected]
Abstract
Sweet potatoes are originally from South American, and they grow at higher temperatures. If sweet potatoes encounter low temperatures, the growth of leaf length, leaf width, petiole length, root length, root diameter, stem length, and leaf number will be remarkably reduced. The reduction of elongation growth of the epidermal cells in above organs can be observed using a microscope.
Sweet potatoes grow well with appropriate water supply. However, the growth of sweet potato will be affected by flooding or water deficit stress. When sweet potatoes were inflicted by flooding, the root weight and root number were reduced but the shoot weight was increased. If sweet potatoes were inflicted by flooding at the early growing stage, the growth of sweet potato would recover after flooding. If sweet potatoes were inflicted by flooding at the middle growing stage, the growth of sweet potato would not recover after flooding.
When sweet potatoes were under the water deficit stress, the shoot fresh weight, branch number, leaf area, maximum root diameter, root number, root weight, and biological yield would be reduced. Likewise, the net photosynthetic rate (Pn), stomatal conductance, transpiration rate, chlorophyll content of sweet potato leaves would also be reduced.
Sweet potatoes have better soil salinity tolerance than other crops. The growth of sweet potato was not significantly affected with the salt concentration of 0.2-0.4%. If the salt concentration was greater than 0.8%, the growth would be significantly reduced. If th salt concentration was greater than 1.6%, no sweet potatoes could survive. When sweet potatoes were under the salt stress, the water potential, relative water content, photosynthetic rate (Pn), stomatal conductance, and transpiration rate of sweet potato leaves would be reduced.
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But the intercellular CO2 concentration and ABA content of sweet potato leaves would be increased with the increase of the salt concentration.
To ease the change of climate, the strategies of sweet potato cultivation include (1) Clipping vines or the use of growth regulator reagents to control the yield of vines and increase the yield of tuberous roots during flooding. (2) Using drainage treatment to reduce the damage of sweet potatoes after flooding. (3) Applying calcium chloride or paclobutrazol for improving the flooding and chilling tolerance of sweet potatoes. The breeding strategies are (1) Using wild sweet potato varieties as the drought resistance parent. (2) Using EMS to induce mutation for screening sweet potato varieties with better salt resistance. (3) Using stress tolerant genes to transform sweet potato varieties with the ability of drought, chilling, heat, and salt resistance.
圖 1 台農 66 號在淹水下塊根重、塊根直徑、塊根個數之生育情形
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圖 2 台農 66 號在淹水下莖葉重之生育情形
圖 3 台農 66 號種植後第 45 天淹水 6 天塊根重及塊根個數之生育情形
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圖 4 台農 66 號在種植後第 100 天淹水 6 天塊根重及塊根個數之生育情形
圖 5 台農 66 號在種植後第 45 天及 100 天淹水 6 天莖葉之生育情形
圖 6 淹水後不同節位甘藷塊根生長情形
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圖 7 甘藷放置於 12℃及 28℃下以電子顯微鏡觀察葉、莖及根之細胞生育情形
圖 8 在乾旱下甘藷葉片之淨光合速率、氣孔導度、蒸散速率及細胞間隙之 CO2 濃度之 表現情形
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圖 9 甘藷品種在不同鹽分濃度下之相對含水量、水勢、氣孔導度、細胞間隙之 CO2濃 度及 ABA 含量之表現情形
圖 10 施用鈣肥對甘藷所含 4 種酵素活性之影響
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圖 11 施用巴克素對甘藷所含 4 種酵素活性之影響
圖 12 導入 Polyamines 基因在甘藷莖葉及塊根之 Polyamines 含量
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圖 13 導入 Polyamines 基因之甘藷品系之塊根
表 1 甘藷品種在乾旱及灌溉處理下之生育情形
表 2 甘藷品種在不同鹽分濃度下之光合速率、蒸散速率及水分利用率之表現情形
表 3 嘉義地區施用生長調節劑後之莖葉生長情形
126 表 4 屏東地區施用生長調節劑後之莖葉生長情形
表 5 嘉義地區施用生長調節劑後之塊根生長情形
表 6 屏東地區施用生長調節劑後之莖葉生長情形
表 7 不同排水量對採收後塊根腐爛率之影響
表 8 施用巴克素對甘藷對寒害之抵抗性
表 9 各材料之抗旱系數、產量及乾物率比較
128 表 10 y2、y6 雜交 F1 代主要性狀表現
表 11 y2、y6 雜交 F2 代入選優良品系產量結果
表 12 誘變品系在不同鹽分濃度下之表現
表 13 PEG6000 濃度對栗子香之懸浮細胞存活率之影響
表 14 選拔品系之耐旱系數
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表 15 導入 Polyamines 基因之甘藷品系莖葉及塊根性狀之表現