研究報告/第87号

農業・園芸総合研究所研究報告

一覧へ戻る

第87号：2019年3月発行

第87号抄録

原著

カラーピーマン果実の着色促進に関する研究

吉田千恵

Studies on Color Development in Sweet Pepper (Capsicum annuum L.) Fruit
with reference to the fruit harvested at breaker stage of mature-green fruit

Chie Yoshida

催色期に収穫したカラーピーマン果実の着色促進について,温度,植物ホルモンおよび光照射の影響について調査を行った。処理温度は20～25℃程度が適温であったが,温度だけでは着色促進効果は少なく,薄赤色の果実となった。また,エチレンとジャスモン酸メチルの植物ホルモン処理による追熟効果は期待できなかった。一方,20℃で蛍光灯を用いて光照射を行ったところ,照射時間および照射強度が高まるほど,着色促進効果が認められた。カラーピーマンの着色には,温度とともに光条件が大きく関与することが明らかとなった。さらに,効率的な着色促進方法の検討を行い,20℃の条件で催色期の果実に対して100 µmol・m-2・s-1程度の光照射を3日間行い,その後4日間の暗黒処理で販売可能な着色具合となることを明らかにした。

〔キーワード〕着色,パプリカ,光照射,温度,植物ホルモン

＜Summary＞

Effects of temperature, phytohormones, and light on the coloring of fruit were examined in sweet pepper (Capsicum annuum L.) fruits harvested at the breaker stage of mature green fruit. Although coloring was promoted at 20 to 25℃ in the dark, the fruit reached only a pale red. Changes in the color were not promoted when either ethylene or methyl jasmonate was applied under a dark condition. Although the color value increased when both phytohormones were simultaneously applied, the effects were insufficient for the force –ripening of fruit. On the other hand, irradiation with a fluorescent light under 20℃ markedly promoted the coloring of the fruit. The fruit achieved a bright red color more quickly with a higher irradiance. There results indicate that light irradiation plays an important role in the coloring of sweet pepper fruit at an optimal temperature. Further, the expression of carotenoid biosynthetic genes in sweet pepper fruit with light irradiation of different wavelength (red(660 nm) or blue(445 nm) light) was investigated. Gene expressions of phytoene synthase (Psy), and capsanthin synthase (Ccs) were markedly induced after 1 day of light irradiation regardless of varying wavelength light. Other carotenoid biosynthetic genes phytoene desaturase (Pds), ζ-carotene desaturase (Zds), lycopene β-cyclase (LcyB), zeaxanthin epoxidase (Ze), and β-carotene hydroxylase (CrtZ-2) were also induced to highr than the dark control.
 An efficient coloring merhods by the combination of light irradiation and dark processing were examined in sweet pepper fruit harvested at breaker stage of mature-green fruit. Therfore, fruit that is colored to 50% or more by light irradiation can achieve market levels of coloring in approximately 4 days by maintaining the fruit at 20℃ and using dark processing. This combination of light irradiation and dark processing may potentially improve the ripening process efficiency and preserve the market value of fruit.