【作者】 刘扣生；

【导师】 寿森炎；

【作者基本信息】 浙江大学 ， 蔬菜学， 2004， 硕士

【摘要】 壳聚糖是甲壳素脱去乙酰基后得到的一种高分子阳离子多聚糖，具有安全无毒，抑菌、可食和生物降解等多种特性，壳聚糖几其衍生物已被广泛地应用于医药、农业、食品、化工、环保等多个领域。由于壳聚糖的分子结构与植物细胞壁结构相似，因而作为新型的植物生长调节剂在作物上应用具有重要的意义。 1、利用不同浓度几丁聚糖对青花菜种子包衣，来研究几丁聚糖对青花菜幼苗生理指标的影响。通过本试验研究表明，不同浓度的几丁聚糖包衣对青花菜幼苗的还原糖、地上部分鲜重、地下部分鲜重及对磷钾的吸收无明显的影响，而显著地增加其中的叶绿素含量、蛋白质含量、地上部分干重、地下部分干重、适当的浓度能增加幼苗叶片中总糖含量和氮的含量；几丁聚糖包衣能显著增加青花菜叶片中游离氨的含量、硝酸还原酶、谷氨酰股合成酶和谷氨酸脱氢酶的活性；几丁聚糖种子包衣能显著增强青花菜幼苗叶片的光合作用和光化学效率。 2、青花菜品种“株绿”和“山水”在不同浓度盐胁迫下施用几丁聚糖，研究几丁聚糖对青花菜耐盐胁迫的影响。研究表明，几丁聚糖明显地增加青花菜种子的发芽率、发芽指数、种子活力指数和耐盐指数，特别是对发芽率较低的种子，几丁聚糖对其作用更加明显；在盐胁迫下，施用几丁聚糖明显地降低青花菜叶片中的MDA含量和降低叶片膜的透性，施用适当的浓度则显著地增加叶片中SOD、POD、PPO的活性，减缓逆境对叶片的伤害，增强植株的抗性，叶片中的脯氨酸含量不断地提高、蛋白质含量不断降低、还原糖基本没有变化，蔗糖、可溶性总糖在盐浓度较低时有下降趋势，后不断地增高，可见植物在受到伤害时分解体内大分子物质生成小分子物质，来增加自身的抗性。 3、通过在青花菜生长期间内喷施几丁聚糖，来研究几丁聚糖对青花菜花球内的酚类物质和品质的影响。研究表明，本研究中，不同浓度几丁聚糖喷施对青花菜花球的叶绿素、类黄酮、绿原酸、多酚总量、可溶性蛋白及可溶性总糖的含浙江大学硕卜学位论文(2004)量有显著增加，其中以浓度为40mgL一’影响最为显著，花球中的叶绿素、类黄酮、绿原酸、可溶性总糖、可溶性蛋白分别较对照提高64.4%、282.5%、35.6%、16.2%、22.7%，苯丙氨酸解氨酶(队L)、多酚氧化酶(PPO)是酚类物质合成中关键酶，花球内酚类物质合成与苯丙氨酸解氨酶的活性没有一定的相关性，而与多酚氧化酶的活性呈正相关。更多还原

【Abstract】 Chitosan, a nature high molecular weight cationic polysaccharide, is normally obtained by the alkaline deacetylation of chitin. Chitosan and its derivatives have a wide range of applications due to their low toxic ,antibacterial activity,edibility and biodegradability, They have been employed, for example, to solve numerous problems in medical , agriculture ,foodstuff environmental and chemical engineering. Because the molecular structure of chitosan is similar with the structure of cell wall, it has great significance to be applied in plants as a new plant growth regulator.1.Seeds of Broccoli were film-coated with chitosan of different concentration.Our results showed that film-coating with chitosan had no significant effect on fresh weight of ground parts and roots of Broccoli seedlings.And there was no significant effect on the absorption of N and K.But film-coating significantly improved the content of chlorophyll and protein in seedling leaves. It also improved the dry weight of ground parts and roots of cauliflower seedlings. Film-coating with chitosan of appropriate concentration can increase the content of total soluble sugar and N in seedling leaves. Film-coating with chitosan significantly improved the content of free ammonium ,the activity of NR, GDH and GS, and film-coating markedly increased photosynthetic captivity and photochemical efficiency of PS II reaction center( PS II).2.We sprayed chitosan on "zhulv"and "shanshui"-two variation of Broccoli under salt stress to investigate the effect of chitosan on salt tolerant of Broccoli.The results showed chitosan significantly increased the germination percentage, germination index and vigor index of Broccoli seeds and increased the salt tolerance index of Broccoli seedings. The effect was more significant on seeds of low germination percentage.Under salt stress ,chitosan significantly decreased the MDA content and membrane permeability of Broccoli leaves.Activities of SOD,POD and PPO in Broccoli leaves was significantly promoted treated with chitosan . Proline content in leaves continuously increased ,while protein content continuously decreased. Reducing sugar content changed little .Content of sucrose and totalsoluble sugar decreased a little under low salt concentration and increased late with the increase of salt concentration.It indicated that plants decompose macromolecular substances to small molecule substance to improve their tolerance captivity under stress.3.Spraying with chitosan of different concentration significantly increased the content of chlorophyll ,anthoxanthin ,chlorogentic acid, polyphenal ,soluble protein and total soluble sugar of Broccoli flowers. 40 mg L-l chitosan showed the most remarkable effet,compared to control, the content ofchlorophyll ,anthoxanthin ,chlorogentic acid, total soluble sugar and soluble protein of treated Broccoli flowers increased by 64.4%,282.5%,35.6%,16.2% 22.7% respectively.PAL and PPO are key enzymes in synthesize of phenolics.No relation was found between phenolics synthesize and PAL activity in Broccoli flowers,but it showed positive relation between phenolics synthesize and PPO activity.更多还原