採收高度對空心菜產量及生長性狀影響之研究

Effects of Harvesting Heights on the Yield and Growth in Ipomoea aquatica Forsk

以不留節位、留一節、留二節等不同高度對空心菜連續進行採收六次，留節位處理萌生的枝梢數較多，平均單株鮮重較重，採收間期愈短，節位處理效果愈顯著。連續採收後期，留二節採收枝梢數仍然最多但形態纖細，不留節位採收枝梢雖仍最少，但每個枝梢平均莖粗較粗，生長較健壯，採收節位處理間，平均每株之鮮、乾重無顯著差異。連續低節位採收會造成較高的死亡率，但以留二節採收，雖然產量高，枝梢數較多，但枝梢較纖細，在產業上建議以產量亦高，枝梢品質仍佳的留一節高度採收。留節位採收處理所萌生的枝梢節間較長，葉形較為橢圓，形態上趨於成熟，不留節位採收，枝梢節間較短，葉形較狹長。試驗植株因株齡已達4個月以上，始花節位（第7節）較剛播種之實生苗低（第11-14節），採收節位高低對開花節位並無影響。

Water spinach was harvested repeatedly at different heights for six times. Plants harvested at heights of first-node of second-node above ground level had more lateral shoot numbers and higher fresh weight than plants harvested just above ground level. In addition, shorter harvesting intervals as above treatment showed more significant effect on yields. However, after consequent harvests, plants harvested at second-node from basal part had thinnest lateral shoots among all treatment, and had no significant difference on fresh weight. On the basis of harvesting at near ground level resulted in higher mortality ratio and harvesting at second-node resulted in unacceptable thin shoots, harvesting at first-node above ground level provided marketable yield and quality of lateral shoots of water spinach. The sprout shoots harvested at height of first-node or second-node above ground level had longer internodes and had more elliptical leaves. Both characters were belonged to mature morphology.