Response of Early-season Asian Pear ‘Hanareum’ Treated with GA4+7 to Postharvest Application of 1-methylcyclopropene (1-MCP)

Abstract

본 연구에서는 지베렐린(<TEX>$GA_{4+7}$</TEX>)을 0, 0.5, 1.2, 2.4% 농도로 조생종 '한아름' 배에 처리하고 수확 후 에틸렌 작용 억제제인 1-methylcyclopropene(1-MCP)를 <TEX>$1{\mu}L{\cdot}L^{-1}$</TEX> 농도로 처리한 후, 20일간의 상온유통기간 중 과실품질 및 생리장해 발생에 미치는 영향을 조사하였다. 상온유통 기간 중 감모율의 변화는 <TEX>$GA_{4+7}$</TEX> 농도와 관계없이 증가하는 경향을 보였으며, 1-MCP 처리의 경우 상온유통 기간이 증가함에 따라 감모율이 약간 감소하는 것으로 나타났고 <TEX>$GA_{4+7}$</TEX> 농도가 증가함에 따라 1-MCP 처리 효과는 떨어졌다. 상온유통 10일에 1-MCP를 처리하지 않은 모든 과실에서 경도가 급격하게 감소하였던 반면 1-MCP를 처리한 과실의 경우 상온유통 15일까지 30N 이상의 높은 경도를 나타내었다. 그러나 <TEX>$GA_{4+7}$</TEX> 처리 농도가 증가할수록 1-MCP 처리 효과는 떨어지는 것으로 조사되었다. 1-MCP를 처리한 과실의 경우 상온유통 기간 동안 가용성고형물과 산함량이 높게 나타났으며, 과피색의 경우 <TEX>$L^*$</TEX>(밝기) 및 hue angles은 높게 조사되었지만 <TEX>$a^*$</TEX>(적색도)의 경우 1-MCP 무처리에 비해 낮게 나타났다. 상온유통 중 에틸렌 발생량은 <TEX>$GA_{4+7}$</TEX> 처리 농도에 영향을 받지 않았고 1-MCP 처리는 에틸렌 발생량을 낮추지 못하는 것으로 조사되었다. 반면 1-MCP 처리 과실의 호흡률은 상온유통 20일간 유의하게 낮게 조사되었는데 1-MCP 처리 효과는 지베렐린을 처리하지 않은 구에서 가장 크게 나타났고 <TEX>$GA_{4+7}$</TEX>의 농도가 증가함에 따라 호흡률 감소 효과도 떨어졌다. 한편 1-MCP 처리는 상온유통 중 발생하는 과심갈변이나 분질과 같은 생리장해 발생 경감효과를 보여, <TEX>$GA_{4+7}$</TEX> 농도와 상관없이 상온유통 15, 20일 동안 과심갈변과 분질과의 발생을 억제하였다. This study was conducted to investigate the effect of 1-methylcyclopropene (1-MCP, <TEX>$1.0{\mu}L{\cdot}L^{-1}$</TEX>), a known ethylene action inhibitor, on fruit quality and incidence of physiological disorders during a simulated marketing period at <TEX>$25^{\circ}C$</TEX> for 20 days in early-season Asian pear (Pyrus pyrifolia Nakai) 'Hanareum' that had been treated with 0, 0.5, 1.2 or 2.4% <TEX>$GA_{4+7}$</TEX>. Weight loss of stored fruits increased with <TEX>$GA_{4+7}$</TEX> concentration, and the 1-MCP treatment slightly reduced the weight loss rates during the marketing period. Flesh firmness decreased abruptly in all 1-MCP-untreated fruits as the storage period extended to 10 d, whereas the firmness of 1-MCP-treated fruits remained high (> 30 N) during 15 days shelf-life. The effect of 1-MCP was significantly reduced when fruits were subjected to increased GA concentration. Higher soluble solids content and acidity during extended shelf-life were also apparent in 1-MCP-treated 'Hanareum' pears. The L-values (lightness) and hue angles of 1-MCP treated samples were higher than those of controls during 20 days shelf-life, but the a-value (redness) was lower in 1-MCP treated fruits. 1-MCP treatment did not decrease the level of ethylene evolution regardless of <TEX>$GA_{4+7}$</TEX> concentration during shelf-life in early-season Asian pear 'Hanareum'. By contrast, 1-MCP treatment decreased the respiration rate significantly during shelf-life. The efficacy of 1-MCP was greatest in the GA-untreated fruit and was reduced as the <TEX>$GA_{4+7}$</TEX> concentration increased. 1-MCP treatment influenced the severity of physiological disorders including core browning and mealiness: 1-MCP treatment completely blocked the incidence of core browning of during 15 days shelf-life, and reduced the severity of mealiness during 20 days shelf-life regardless of <TEX>$GA_{4+7}$</TEX> concentration. Based on our results, we conclude that the use of <TEX>$1{\mu}L{\cdot}L^{-1}$</TEX> 1-MCP can be of great benefit for maintaining quality and preventing physiological disorders in early-season pear cultivar 'Hanareum' pear, whereas its efficacy decreases with the concentration of <TEX>$GA_{4+7}$</TEX> whereas its efficacy gradually decreases when the concentration of <TEX>$GA_{4+7}$</TEX> paste increased.