Huang Hua, Wang Ling, Qiu Diyang, Lu Yusheng
Institute of Fruit Tree Research, Guangdong Academy of Agricultural Sciences; Key Laboratory of South Subtropical Fruit Biology and Genetic Resource Utilization, Ministry of Agriculture and Rural Affairs, Guangdong Provincial Key Laboratory of Tropical and Subtropical Fruit Tree Research, Guangzhou, China.
Sericultural & Agri-Food Research Institute Guangdong Academy of Agricultural Sciences, Key Laboratory of Functional Foods, Ministry of Agriculture and Rural Affairs, Key Laboratory of Agricultural Products Processing, Guangzhou, China.
Front Plant Sci. 2022 May 12;13:840061. doi: 10.3389/fpls.2022.840061. eCollection 2022.
The plant cuticle, as a lipid membrane covering aerial plant surfaces, functions primarily against uncontrolled water loss. Herein, the cuticle chemical composition and the transpiration of wampee fruit ( (Lour.) Skeels) at the green, turning, and yellow stages in cultivars of "Jixin" and "Tianhuangpi" were comprehensively studied. The coverage of wax and cutin monomers per unit of fruit surface area at the green stage was lower in "Jixin" than in "Tianhuangpi" and increased gradually during development. Cutin monomers accumulated ranging from 22.5 μg cm (green) to 52.5 μg cm (turning) in "Jixin" and from 36.5 μg cm (green) to 81.7 μg cm (yellow) in "Tianhuangpi." The total composition of waxes ranged between 6.0 μg cm (green) and 11.1 μg cm (turning) in "Jixin," while they increased from 7.4 μg cm (green) to 16.7 μg cm (yellow) in "Tianhuangpi." Cutin monomers were dominated by ω-, mid-dihydroxy fatty acids (over 40%), followed by multiple monomers of α,ω-dicarboxylic acids with or without added groups, α-monocarboxylic acids with or without ω- or mid-chain hydroxy or mid-epoxy groups, primary alcohols, and phenolics. The very-long-chain (VLC) aliphatic pattern of cuticular waxes was prominently composed of -alkanes (ranging from 21.4% to 39.3% of total wax content), fatty acids, primary alcohols, and aldehydes. The cyclic waxes were dominated by triterpenoids (between 23.9 and 51.2%), sterols, and phenolics. Water loss in wampee fruit exhibited linear changes over time, indicating an overall monofunctional barrier to transpiration. Permeance for water in wampee fruit was higher at the green stage than at the yellow stage in both "Jixin" and "Tianhuangpi," which showed a negative correlation with the changes of VLC -alkanes. The results showed the cuticular chemicals, including cutin monomers and waxes, in wampee fruit and further indicated the potential contributions of the cuticular chemical composition to the physiological functions in fruits.
植物角质层作为覆盖植物地上部分表面的脂质膜，主要功能是防止水分无节制流失。在此，对“鸡心”和“甜黄皮”品种黄皮果实绿色、转色和黄色阶段的角质层化学成分及蒸腾作用进行了综合研究。“鸡心”品种绿色阶段果实单位表面积蜡质和角质单体的覆盖量低于“甜黄皮”，且在发育过程中逐渐增加。“鸡心”品种角质单体积累量从绿色阶段的22.5μg/cm²增加到转色阶段的52.5μg/cm²，“甜黄皮”品种则从绿色阶段的36.5μg/cm²增加到黄色阶段的81.7μg/cm²。“鸡心”品种蜡质的总组成在绿色阶段为6.0μg/cm²，在转色阶段为11.1μg/cm²，而“甜黄皮”品种从绿色阶段的7.4μg/cm²增加到黄色阶段的16.7μg/cm²。角质单体以ω-、中双羟基脂肪酸为主（超过40%），其次是带有或不带有附加基团的α,ω-二羧酸、带有或不带有ω-或中链羟基或中环氧基的α-单羧酸、伯醇和酚类的多种单体。角质层蜡质的超长链（VLC）脂肪族模式主要由正构烷烃（占蜡质总含量的21.4%至39.3%）、脂肪酸、伯醇和醛类组成。环状蜡质以三萜类化合物（23.9%至51.2%）、甾醇和酚类为主。黄皮果实的水分流失随时间呈线性变化，表明其对蒸腾作用总体上是单功能屏障。“鸡心”和“甜黄皮”品种黄皮果实绿色阶段的水分渗透率均高于黄色阶段，且与VLC正构烷烃的变化呈负相关。结果表明了黄皮果实角质层化学成分，包括角质单体和蜡质，进一步表明了角质层化学成分对果实生理功能的潜在贡献。
