全株氣體交換系統及田間管理對草莓光合作用之影響

Abstract

調查田間的植物生理表現，可協助研究者判定田間環境，如光照強度或溫度，與栽培管理對於作物生長與產量之影響。測量草莓(Fragaria ×ananassa Duch.)之全樹冠氣體交換率為本研究目的之一，故設計出一擁有透明樹冠葉箱之可攜式全樹冠氣體交換系統。透明樹冠葉箱使得穿透之日光強度下降17%，而藉由調整系統內空氣流速，使得氣流有足夠時間與草莓植株進行氣體交換，並帶走累積於樹冠葉箱之多餘熱能，此一設備可獲得草莓植株生長量與¬二氧化碳及水氣交換率之良好相關性。本研究並調查於北台灣盛行之塑膠棚栽培系統，對於草莓生長與全株氣體交換之影響。塑膠棚栽培系統使得日照強度下降30%，造成 ‘豐香’草莓全樹冠光合作用率減少30%。於產季後半季時，植株葉面積減少35%，並由於日照強度不足使得草莓植株乾物重下降60%。此研究另調查蟎類藥劑fenpyroximate對於草莓生長與葉片氣體交換之影響，以水溶液濃度為0、1及2 ml•l-1之5%fenpyroxmate噴施於‘豐香’草莓葉片進行試驗。草莓葉片淨光合作用會於蟎類藥劑fenpyroximate噴施一日後暫時上升,但fenpyroximate對於草莓葉片生長與花朵數量無顯著性影響。這些結果指出，於塑膠棚之日照強度降低，可能導致草莓產量下降。而於非有機生產之草莓園，蟎類藥劑fenpyroximate於正常使用濃度下，因不會對植株造成永久性傷害，仍為有效之蟎類控制方法。

Investigation of plant physiology performances in fields could assist researchers to evaluate the effects of environment condition and cultural practices on crop growth and yield. To measure whole canopy gas exchange of strawberry (Fragaria ×ananassa Duch.) plants, we designed a portable whole canopy gas exchange system with clear canopy chambers. The clear canopy chambers allow sun light penetration with 17% decrease of light intensity. Air flow was adjusted to maintain a good retention time for gas exchange while minimizing heat accumulation in the chamber. Good correlations among plant size, CO2, and H2O exchange were obtained. We also investigated strawberry growth and whole plant photosynthesis under the plastic tunnel system which is popular in Northern Taiwan. The plastic tunnel system caused 30% declination of light intensity and resulted in 30% reduction of whole canopy photosynthesis in ‘Toyonoka’ strawberries. Consequently, plants under plastic tunnels had 35% less total leaf area and 60% less dry weight then the control. In the third part of this research, we assessed the effects of miticide fenpyroximate on growth and leaf gas exchange in strawberries. 5% fenpyroximate at the concentrations 0, 1, or 2 ml•l-1 were applied to ‘Toyonoka’ strawberry leaves. The leaf net photosynthesis would increase temporarily one day after fenpyroximate application, but there was no significant influence of fenpyroximate on leaf and flower growth. These results showed that insufficient of light intensity may cause strawberry yield loss, but fenpyroximate is still a good method in non-organic production systems for strawberries protection in the proper application rate which did not injury crops permanently.