套袋對蓮霧(Syzygium samarangenes Merr. et Perry)果實著色與品質的影響

Abstract

蓮霧(Syzygium samarangenes Merr.et Perry)週年生產，但冬季果實小、夏季果實淡紅色為產業問題，本論文探討光度對果皮花青素含量的影響，及溫度對果皮花青素含量與果實重量的影響。袋內透光率與溫度乃藉由不同材質之果實袋套於果實來調節。 蓮霧果皮在黑暗中仍可累積花青素，光照可顯著增加累積量，但達最高累積量之光照度，則因季節有所不同。冬果試驗中，以15%-90%透光率之套袋果實，果皮累積較高量花青素(6.3±0.4μmol•cm-2)；4%透光率之套袋處理者，其累積量為最高量之80%，而不透光之黑暗處理者仍有最高量之50%。春果試驗結果與冬果試驗結果相似，但4%至15%透光率處理者有果皮花青素高含量(8.3±0.1μmol•cm-2)，52%透光率之套袋處理者，其果皮花青素含量減少約20%，而黑暗處理者仍有約65%之累積量。鋁箔外加泰維克袋的黑暗處理之果實，在採收前1週換52%透光率之袋子，於冬果可增加累積量，春果則無影響。比較果實生長發育的時期的溫度及光照量，春果3月均溫22℃，而冬果1月均溫18℃；換算每日最大日照強度成袋內光強度來看，春果果實在最大光度68至257μmol•m-2•cm-2時，即可累積最高量的花青素，且最大光度超過890μmol•m-2•cm-2，將不利果皮花青素的累積；而冬果則需197至1180μmol•m-2•cm-2方可累積最高量的花青素。春果發育時期氣溫較高、光需求較低；而冬果發育時氣溫較低，光需求較高，光照與溫度可能是影響果實著色的重要因子，但仍須更進一步的探討。 2009年冬季袋內溫度對果實重量之影響試驗，鋁箔外加泰維克袋較白色開窗紙袋處理者高4.4℃，且果實長、寬、重、體積較後者大；如中果期將鋁箔外加泰維克袋換成白色開窗紙袋，其果實長、寬、重量、體積與白色開窗紙袋處理者無顯著差異，顯示果實生育後期為果實膨大關鍵期。此種結果在2010年冬果試驗未能再現，因落果率增加影響果實重量，干擾數據。

Wax apple (Syzygium samarangenes Merr.et Perry) can produces fruits all-year-round in Taiwan; however, to enlarge winter fruits and darken the skin color of summer fruits are two major priority issues. Thus, the objective of this study was to evaluated the effect of light permeability and temperature on the synthesis of anthocyanins and fruits weight. The light permeability and temperature was adjusting by bagged the fruits with varieties of bags. Fruit skin of wax apple may accumulate anthocyanins without light but light may enhence accumulation; however, the light intensity required to produce highest amount of anthocyanins varies among different seasons. In winter, fruits developed in 15%-90% permeability bag had highest anthocyanins content (6.3±0.4μmol•cm-2 ), in 4% permeability bag had 80% of the highest content, and in dark had 50% of the highest content. In spring, the highest content (8.3μmol•cm-2) appeared in the fruits developed under 4%-15% permeability, 52% permeability resulted in 50% decrease from the highest, and fruits developed in the dark accumulated 65% of the highest. Exposing to light through bags of 52% permeability for the dark treated fruits 1 week before harvest increased the anthocyanins content in winter fruits but not spring fruits. The average temperatures of the fruit developing periods of the winter and spring fruits were 22oC and 18 oC; whereas, the light intensities required to obtain highest anthocyanins content were 197-1180μmol•m-2•cm-2 for winter fruits, and 68-257μmol•m-2•cm-2 for spring fruits. Temperature and light intensity may play important roles in skin coloring in wax apple; however, more research is needed to prove. The effect of temperature on fruit weight was conducted in winter of 2009. Tyvek-foil bag increased fruit developing temperature by 4.4oC than white paper bags, which resulted in increase of fruit length, width, weight, and volume; while switch Tyvek-foil bags to white paper bags at middle stage of fruit developing diminish the increase. The result revealed that he critical period for fruit enlargement was after middle stage of the fruit development. However, the effect of temperature on fruit development was not repeated in experiment of 2011 winter due to severe fruit drop.