【作者】 张永卓；

【导师】 罗正荣；

【作者基本信息】 华中农业大学 ， 果树学， 2004， 硕士

【摘要】 中国甜柿是柿（Diospyros kaki Thunb.）在长期栽培过程中，由于遗传变异和自然、人工选择的作用，分化出的宝贵资源，但目前还缺乏有效地利用。这主要表现在两个方面：首先，除‘罗田甜柿’外，中国甜柿的甜涩性状尚未进行系统鉴定；其次，中国甜柿种质的超低温保存体系尚未见报道。本研究以中国甜柿为试材，主要围绕甜涩性状的鉴定和超低温保存作了两方面的工作，取得以下结果： 1．通过对可溶性单宁含量的测定和单宁细胞的切片观察发现，在果实接近成熟时，‘罗田甜柿’、‘秋焰甜柿’、‘宝盖甜柿’、‘湘西甜柿’、‘华柿一号’果肉中单宁细胞较小，所占比例较低，可溶性单宁含量低于0.2％，基本达到自然脱涩，且其脱涩与否与种子的多少无关。因此，可以断定，中国甜柿属于完全甜柿。 2．探讨了蔗糖浓度、装载和PVS₂处理时间对中国甜柿种质超低温保存后成活率的影响，建立起中国甜柿休眠芽茎尖包埋—玻璃化法超低温保存的技术体系，即：长约1mm的茎尖用海藻酸钙包埋后，在含有0.3 mol/L蔗糖的改良MS（Murashigeand Skoog,1962）培养基（KNO₃和NH4NO₃减半）上预培养1d，室温（25℃）下PVS₂处理2 h后快速投入液氮（LN），1h后取出，在40℃水浴中化冻1～2 min，用含有1.2 mol／L蔗糖的改良MS培养液洗涤20 min，接种于含ZT（玉米素）2.2mg／L、PVP（聚乙烯吡咯烷酮）600 mg／L的改良MS培养基，暗培养3～5 d，转移至正常光下，最高成活率接近100％；再生植株生长和分化正常。更多还原

【Abstract】 Non-astringent persimmons originated in China are precious resources, which were produced during the long-term cultivation under the effect of genetic variation and selection naturally or artificially. However, at present, those resources have not been used effectively, which shows in two sides: firstly, the property of natural loss of astringency has not been identified by the numbers as so far. Secondly, the procedure for cryopreservation of dormant shoot tips from non-astringent persimmons originated in China needs optimizing furthermore.In order to make full use of our invaluable non-astringent persimmoms germplasm and create new better cultivars or types with the virtues of big fruits, few seeds and fine quality, non-astringent persimmons originated in China were used as materials to identify the property of natural loss of astringency and cryopreserve dormant shoot tips, and the major results as follows:1. By the observation of the tannin cells in fruits flesh and the determination of the soluble tannin content, we found that, area of per tannin cell became smaller, the proportion of tannin cells in per unit area flesh was lower also, and the content of soluble tannin was under 0.2%. Therefore, a conclusion was made down by us: as the property of natural loss of astringency was concerned, ’Luotiantianshi’, ’Qiuyantianshi’, ’Xiangxitianshi’, ’Baogaitianshi’, ’Huashi N0.1’ all belong to pollination constant non-astringent persimmons.2. In this research, effect of sucrose content, loading time, and the time expose to PVS2 on the survival rate of the shoot tips after cryopreserved, and an approach for cryopreservation of dormant shoot tips was entablished by encapsulation-vitrification method, namely, excised shoot tips about 1 mm in length, were encapsulated into alginated-gel beads. Then alginated-coated shoot tips were precultured on a modified MS basal medium supplemented with increasing sucrose containing of 0.3, 0.5, 0.7, 1.0 mol/L for 1 day. After preculture, encapsulated shoot tips were loaded with a mixture of 2 mol/L glycerol plus 0.4 mol/L sucrose for 20 min. Following loading, encapsulated shoot tipswere dehydrated with a highly concentrated vitrification solution (PVS2 ) for 2 hat 25 癈, and then plunged directly into liquid nitrogen. After rapid warming in water for about 1-2 min at 40 , the shoot tips were rinsed with the modified MS (Murashige and Skoog, 1962) medium containing 1.2 mol/L sucrose for 20 min, and then cultured on the modified medium with 2.2 mg/L ZT and 600 mg/L PVP in dark prior to exposure to the light. The best survival rate of encapsulation vitrified shoot tips amounted to nearly 100% and no abnormality was observed.更多还原