【作者】 张建农；

【导师】 曹孜义；

【作者基本信息】 甘肃农业大学 ， 作物栽培学与耕作学， 2005， 博士

【摘要】 本研究以典型的籽用西瓜种质资源为材料,不同类型的西瓜品种为对照,研究了籽瓜种质资源的亲缘关系,籽瓜果实耐贮性生理机理、籽瓜资源相关性状的遗传规律及在籽、瓤品种改良中的应用,结果如下:1对4个籽用西瓜、2个野生西瓜和不同生态类型瓤用西瓜等34个品种(系)进行植株生长期、种子大小和果实相关性状的观察、RAPD标记和聚类分析,结果表明,靖远大板在种子大小、种子千粒重、果实发育期、可溶性固形物含量等性状上与瓤用西瓜有明显的差异,多数性状表现极端类型,但其他性状未发现特殊表现。内蒙白瓜籽和两个红瓜籽品种亦有一定的差异,但差异幅度较小;RAPD标记和聚类分析显示,16个引物共扩增出157条DNA带,其中67条表现多态性,占总带数的42.68%;34份材料中,两个野生类型与栽培品种遗传距离最远,野生类型之间的遗传距离也相对较远,大多数栽培品种之间的遗传距离较近,且生态类型没有特异性表现。由此表明西瓜栽培品种的遗传基础相当狭窄;籽用西瓜中靖远大板与多数瓤用西瓜亲缘关系相对较远,但其差异不足以形成一个新的变种;其余3个籽瓜品种与瓤用西瓜亲缘关系更近。2以黑瓜籽籽瓜品种靖远大板为材料,西农8号西瓜为对照,研究果实采后细胞壁结构及相关成分和酶活性的变化。结果显示:贮藏前期籽瓜果实硬度较大、中果皮原果胶含量呈上升的趋势,25天后下降平缓,可溶性果胶含量随贮藏期的延长逐渐上升,后期变化比较平缓,一直维持在一个相对较高的水平;西瓜果实中果皮硬度、原果胶含量与籽瓜相比总体较低,且随贮藏时间的延长差距逐渐拉大,可溶性果胶含量相对较高。籽瓜PE酶、PG酶活性变化平缓,贮藏中始终呈缓慢上升或下降的趋势,而西瓜两种酶活性变化幅度较大,前期较低,贮藏中期达到一高峰,然后急速下降。超显微结构观察结果显示,贮藏期中果皮和果肉组织细胞壁、细胞膜系统逐步解离,表现为细胞壁中胶层、微纤丝分解,细胞膜被破坏和细胞器消失,西瓜相关结构大幅度的早于、重于籽瓜,至实验结束时,已基本丧失其原有的结构,而籽瓜还维持一定程度的完整性。贮藏期中,籽瓜SOD酶活性持续升高、前期POD酶活性逐步上升,至35天时达到最大值,此后开始平缓下降,而西瓜SOD酶和POD酶活性贮藏初期与籽瓜相当或接近,后期活性急剧下降;籽瓜超氧阴离子自由基产生速率和丙二醛含量整体较低,且增加幅度较小。由此认为,籽瓜贮存期原果胶含量较高、PE酶、PG酶活性变化平缓,超氧阴离子自由基产生速率低,丙二醛含量增加缓慢、SOD酶和POD酶活性持续更多还原

【Abstract】 The edible seed watermelon germplasm resources and different types watermelon were used as materisls to research the genetic diversity of the edible seed watermelon, fruit bear-storage mechanism of the black-seed edible seed watermelon and breeding for seed or flesh with the germplasm resources.The results were as following:1 34 cultivars or strains incloud 4 edible seed watermelons, 2 wild watermelons and the different ecology type flesh watermelons were used to the research on the characters observation of plant growth period, the seed size and the fruit,RAPD mark,and cluster analysis. The results show that the seed size, weight of 1000 seeds, fruit development period and soluble solid content etc.of Jingyuandaban had obvious differences with flesh watermelons,most of them were extreme type, but the specially displays had not observe in other characters .The other 3 cultivars of edible seed watermelon, Neimengbaiguazi, Ninghong and Xinhong also had the certain difference with the flesh watermelon but range of difference was smaller; The RAPD mark and cluster analysis demonstrationed that 157 DNA bands amplfied with 16 random primers were observed and 67 of them were polymorphic.An average proportion of polymorphic loci was 42.68%. 34 cultivars or strains were classified into two sub-groups, which were cultivars and wild types, two wild types had the certain difference eath other, the genetics distance of most cultivars was smaller and had not related with the ecology types. From above indicated that the genetics background of cultivars of watermelon was quite narrow;The Jingyuandaban was far relation with the flesh watermelons, but its difference was not enough to divided another new variation.2 The edible seed watermelon‘Jingyuandaban’, comparing with flesh watermelon’Xinong-8’were used to research fruit bear-storage mechanism.The result shows:During early storage, the furit firmness of edible seed watermelon was relatively high, changing trend of propectin content was going up before 25 days,then droping gently,soluble pectin content gradually rised,and had kept high level in later storage; The furit firmness , propectin content of watermelon was lower than of edible seed watermelon, the difference of them gradually raised,and soluble pectin content was high.Pectinmethy lesterase (PE) and polygalacturonase(PG) activity of edible seed watermelon gently risen or comed down in storage; Variation range of PE and PG activity of watermelon were bigger,its rose to height ,then comed down quickly in storage.Ultrastructure of in middle fruit skin and flesh of edible seed watermelon and watermelon showed that cell wall,cell membrane et al were decomposed, middle lamella and micro-fibril were resolved in later storage.Its of them in watermelon were more seriously and early than in edible seed watermelon,and in the end of storage, cell original structure of watermelon was destroyed , but the structure of edible seed watermelon was much better.In storage, SOD activity of edible seed watermelon had kept to rise,POD activity更多还原