不同耐裂性小型西瓜果实力学特性与果皮结构研究

Study on Fruit Mechanical Properties and Rind Structure of Mini-watermelon with Different Cracking Resistance

为揭示小型西瓜果实力学特性及果皮组织结构与耐裂性的关系,以耐裂性不同的8份西瓜种质和1份由易裂亲本201609019与耐裂亲本S1-1111配制的杂交F1代为材料,采用质构仪分析其果实硬度、果实裂应力及果皮韧性,利用石蜡切片法观察其果皮组织结构。结果表明,易裂与耐裂西瓜果实力学特性和果皮组织结构差异显著,耐裂果的西瓜果实硬度、裂应力及果皮韧性更大,果皮细胞排列更加紧密,表皮细胞长厚比值小,外果皮厚,并具有条带状石细胞层。相关性分析表明,果实力学特性与石细胞厚度呈极显著正相关,与外果皮厚度呈显著正相关,与表皮细胞长厚比呈显著负相关。201609019×S1-1111遗传耐裂亲本具有石细胞结构,果实硬度与耐裂亲本差异不显著,裂应力和韧性介于两亲本之间,外果皮厚度变大。201609019和049-2虽果实硬度相近,但果实裂应力、果皮韧性及果皮结构差异明显,耐裂性也不同。评价西瓜果实耐裂性应综合考虑果实硬度、果实裂应力及皮韧性,果实的耐裂性差异是果皮的各层结构综合作用的结果,在西瓜品种选育中可以通过杂交的方式将耐裂性状渗入来改善品种的耐裂性。

In order to reveal the relationship between mechanical properties,skin structure and crack tolerance of mini-watermelon fruits(Citrullus lanatus),8 watermelon germplasms with different crack tolerance and 1 hybrid F 1 prepared from crack tolerant parent 201609019 and crack tolerant parent S1-1111 were used as material,the fruit hardness,fruit cracking stress and peel toughness were analyzed by texture analyzer,and the peel structure was observed by paraffin section method.The results showed that there were significant differences in mechanical properties and rind structure between crack resistant watermelon and easily crack watermelon fruits.The hardness,crack stress and rind toughness of crack resistant watermelon fruits were higher,the rind cells were more closely arranged,the ratio of epidermal cell length to thickness was smaller,the outer rind was thicker and had banded stone cell layer.Correlation analysis showed that fruit mechanical properties were positively correlated with stone cell thickness,positively correlated with exocarp thickness,and negatively correlated with epidermal cell length-to-thickness ratio.201609019×S1-1111 genetic crack resistant parent had stone cell structure,the fruit hardness was not significantly different from the crack resistant parent,the crack stress and toughness were between the two parents,and the outer peel thickness was larger.The fruit hardness of 201609019 and 049-2 was similar,and the fruit cracking stress,peel toughness and peel structure were significantly different,and the crack resistance was also different.Fruit hardness,fruit cracking stress and skin toughness should be considered comprehensively to evaluate watermelon fruit cracking resistance.The difference of fruit cracking resistance was the result of the comprehensive effect of various layers of skin structure,and the crack resistance could be improved by crossing into watermelon varieties.