柑橘果实形态与果皮裂隙发生规律  

Occurrence Rules of Citrus Fruit Shape and Peel Cracks

作　　者：王贤达[1] 张立杰[1] 吴兴明 程德明[3] 李健 WANG XianDa;ZHANG LiJie;WU XingMing;CHENG DeMing;LI Jian(Fruit Research Institute,Fujian Academy of Agricultural Sciences,Fuzhou 350013;Agricultural and Rural Bureau of Yong’an City,Yong’an 366000,Fujian;Fujian Academy of Mechanical Sciences,Fuzhou 350005)

机构地区：[1]福建省农业科学院果树研究所,福州350013 [2]永安市农业农村局,福建永安366000 [3]福建省机械科学研究院,福州350005

出　　处：《中国农业科学》2024年第17期3458-3468,共11页Scientia Agricultura Sinica

基　　金：福建省公益类科研院所专项(2022R1028006);福建省平和县现代农业产业园中央财政奖补资金项目(PH2022-01)。

摘　　要：【目的】研究不同果形柑橘果实的裂隙发生规律,开启认识柑橘采前因田间水分失调导致膨胀裂果的新视角。【方法】根据柑橘果壳结构分层特征,将果壳视为密闭压力容器,依据压力容器壁应力分析方法,阐释各类果形果壳膨胀应力分布与果皮裂隙发生规律。【结果】果壳形态直接影响膨胀应力分布与裂隙规律。(1)椭圆形果实:果形指数FSI<1时,果壳的果顶应力σTop>赤道经向应力σΦ-Mid>赤道环向应力σθ-Mid,因而扁椭圆形果实裂隙多位于果顶,如早熟温州蜜柑C.reticulata Satsuma品系;果形指数FSI>1时,果顶应力σTop<赤道经向应力σΦ-Mid<赤道环向应力σθ-Mid,即长椭圆形果实裂隙多呈纵裂,如‘奈维林娜’脐橙(C.sinensis Navelina Navel);果形指数FSI=1,近圆球形果壳裂隙多位于果壳最薄处dmin,果顶应力与赤道应力比值与其对应部位果壳厚成反比σTop/σMid=dMid/dTop,如‘甜春桔柚’(Spring-sweet Tangelo)裂隙多位于果腰赤道部的果皮最薄处呈环状横裂,而‘纽荷尔’脐橙(C.sinensis Newhall Navel)的裂隙多始于脐顶最薄处。(2)果形近心形文旦柚类果实的果顶凹处易构造膨胀“应力集中”条件,且与砂囊椭球顶部膨胀应力极大点重合,以致果实顶部呈规律性的裂隙,如‘度尾文旦’柚(Citrus grandis Duweiwendan)。(3)在田间水势陡增时,高糖果实的体积膨胀比与裂果率均大于低糖果实。【结论】柑橘果壳裂隙始于果壳膨胀应力最大处,裂隙延伸方向与最大应力方向垂直。果形越偏离球形、果壳厚差异越显著,膨胀应力分布越不均匀,裂果率越高。遇田间水势陡增时,高含糖量果实裂果率大于低含糖量果实裂果率。【Objective】The occurrence rules of cracks in citrus fruits with different fruit shapes were fully investigated to provide a new perspective for understanding the swelling and cracking of citrus fruits caused by field water imbalance before harvest.【Method】Based on the hierarchical characteristics of citrus peel structure,the fruit shell was considered a closed pressure vessel.By using the stress analysis method for the pressure vessel wall,the distribution of shell swelling pressure and the occurrence rules of peel cracks in different types of fruit shapes were evaluated.【Result】The shape of fruit shells affected the distribution of swelling pressure and the occurrence rules of cracks.(1)While the fruit shape index FSI in oval fruit was<1,the stress at the top of the fruit shell(i.e.,σTop)was>equatorial meridional stress(i.e.,σΦ-Mid)and>equatorial circumferential stress(i.e.,σθ-Mid),which explained why the cracks in the oval-shaped fruit were often observed at the top of the fruit,e.g.,the case for the early maturing cultivar Citrus reticulata Satsuma.If the fruit shape index FSI was>1,the stress at the top of the fruit shell(i.e.,σTop)was<equatorial meridional stress(i.e.,σΦ-Mid)and<equatorial circumferential stress(i.e.,σθ-Mid),which could be frequently found in the elongated oval-shaped fruit with many longitudinal cracks like in the cultivar C.sinensis Navelina Navel.As for the fruit shape index FSI was=1,the cracks in the nearly spherical fruit shell were often located at the thinnest part of the fruit shell,and the ratio of stress at the top of the fruit to equatorial stress was inversely proportional to the thickness of the corresponding part of the fruit shell(i.e.,σTop/σMid=dMid/dTop).For example,the cultivar Spring-sweet Tangelo often had circular transverse cracks at the thinnest part of the fruit waist,while the cultivar C.sinensis Newhall Navel cracks started at the thinnest part of the navel top.(2)The concave part of the nearly heart-shaped pomelo fruit was prone to forming

关 键 词：柑橘 果实形态 果壳膨胀应力 裂果 裂隙规律 

分 类 号：S666[农业科学—果树学]