環刻對巨峰葡萄果實品質及光合作用之影響

Abstract

夏果轉色不良是台灣農民以一年二收模式生產巨峰葡萄存在多年之問題，前人指出在葡萄果實轉色時進行環刻處理可促進果實著色，並提高糖度。但環刻可能會影響根部碳水化合儲藏並降低葉片光合速率，而會對次一產季之植株及果實生長產生不良之影響。因此本試驗之目的為調查環刻對巨峰葡萄夏果果實品質及對冬果結果枝生長之影響，並測量環刻後植株氣體交換之變化作為後續研究之參考。 試驗結果顯示著果期結果枝環刻對葡萄果實橫徑及鮮、乾重無顯著影響。轉色期主枝環刻可提高採收時深色果實比率，但對於橫徑、糖度及酸度沒有顯著影響。此外，轉色期主枝環刻對於夏果結果枝內之可溶性糖及澱粉累積以及冬果結果枝生長亦無顯著影響，推測造成此結果枝原因為夏果轉色期環刻之傷口在4週內即癒合，可恢復韌皮部之運輸，使根部可繼續累積供應冬果結果枝生長所需之碳水化合物所致。 環刻處理會立即影響葡萄植株葉片之氣體交換，處理組植株之光合速率在環刻後7至33日內僅為對照組之80~60%（P<0.05），隨著環刻傷口癒合，處理組植株之光合速率逐漸恢復至對照組之水準，但由於氣溫及葉齡老化之關係，兩組植株在試驗後期之光合速率僅2 μmol CO2•m-2•s-1左右。環刻亦會導致植株之氣孔導度及蒸散速率下降，但僅於處理後13至18日間與對照組有顯著差異，因此推測造成環刻後光合速率下降之原因可能與非氣孔因子有關。 根據本試驗結果，轉色期主枝環刻可促進巨峰葡萄夏果轉色，但對糖度影響不顯著，推測原因除了氣候因子外，植株營養生長過於旺盛可能為原因之一，因此在未來研究方面可針對環刻與植株生長之交互作用作更深入之研究。

Poor coloration reduced berry quality and market value of summer crop in ‘Kyoho’ table grapes produced with a double cropping system. Girdling at v&eacute;raison can promote berry coloration and total soluble solid content but the practice might also reduce carbohydrate reserves and leaf photosynthesis rate (Pn). The effect of girdling on berry quality, and the potential negative effects on winter crop as well as leaf photosynthesis in ‘Kyoho’ grapevines were assessed in this study. The result showed that early fruiting shoot girdling did not improve berry diameter, fresh weight, or dry weight. On the other hand, arm girdling at v&eacute;raison increased dark-color berry number. Berry size, TSS and tartaric acid concentration were not affected by girdling. In addition, carbohydrate and starch content in fruiting shoot and growth rate of winter crop shoot didn’t affected by girdling practiced at v&eacute;raison. Leaf Pn were reduced by shoot girdling 7 to 33 days after treatment. Pn of both girdled (G) and control (CK) vines declined throughout the experiment period. Differences of T mmol and gs between CK and G were significant 13 to 18 days after treatment. The result indicated that reduction in Pn of girdling grapevine was not associated with stomatal closure but non-stomatal components.