【作者】 于洋；

【导师】 汪炳良； 施星仁；

【作者基本信息】 浙江大学 ， 园艺学（专业）（专业学位）， 2017， 硕士

【摘要】 小白菜作为夏季浙江地区的主供菜之一,人们对其各项品质要求越来越高。为了筛选出适宜浙江地区夏季生产栽培的小白菜品种,探讨相关栽培技术的改进措施。首先,以七种不同品种的小白菜品种为原料,通过在栽培种植中测定其植物学性状、产量性状、营养品质含量和有害物质硝酸盐的含量。从而筛选出耐热适应性最好、品质最优的小白菜品种。其次,将两个小白菜品种置于不同种植密度的环境中,通过测定其生物学特性,进而探讨在浙江地区夏季时节应选择何种种植密度来保障小白菜生长发育状况最好。最后,通过不同类型的遮阳网覆盖处理,分析小白菜的各项品质指标,以期筛选出最为合适的遮阳网,应用于大规模的生产实践中。以上分析结果可为小白菜的生产应用提供技术指导,具体结论如下:1、7个小白菜品种的模糊型评价分析结果显示,‘日本华冠’、’金品104号’和’夏帝’这三个品种较适合在浙江地区夏季栽培,其耐热适应性较强。对小白菜的营养品质含量和硝酸盐含量测定后发现,’夏帝’的维生素C、可溶性糖、和硝酸盐含量较高,’金品104号’的纤维素含量较高,’金品21号’的叶片中硝酸盐含量较高。最后通过熟食品尝,普遍认为’日本华冠’、’金品104号’和’夏绿’的口感风味较好。通过综合风味与小白菜的植物学性状和营养品质及硝酸盐含量相关性分析后,发现综合风味与植株的单株重和叶宽呈显著正相关性,与硝酸盐含量和纤维素含量都呈显著负相关,与其他性状和品质指标间显著性不明显。2、随栽培密度的增加,各采收期中株高、叶长、叶柄长明显增加,叶宽、叶片数、单株重明显降低,说明一定范围内栽培密度的改变对小白菜的生长发育具有一定规律性的影响。同时,播种密度为100株/m2的设置下,此时小白菜的产量相较于其他播种密度时的产量较高,但当播种密度超过100株/m2后小白菜的产量降低。因此,小白菜更适宜在100株/m2左右的播种密度下栽培。3、不同材质的遮阳网对小白菜生长发育及生理性状的影响较大。试验测定结果显示,塑料薄膜、防虫网、银灰色遮阳网和黑色遮阳网覆盖处理都能够在不同程度上减弱光强,降低栽培环境中的气温和土温,从而使小白菜免受高温强光胁迫。同时,不同的覆盖处理对小白菜生长发育影响的差异较大,其主要体现在株高增高、开展度增大、叶片数增多三个方面。但从小白菜营养品质和硝酸盐含量分析可知,小白菜的维生素C和纤维素含量在遮阳网环境中低于露地栽培,硝酸盐含量高于露地栽培。更多还原

【Abstract】 Summer vegetables mainly consist of Pakchoi in Zhejiang Province,so the quality of pakchoi becomes more and more a major concern in local agriculture.In order to select adapatable pakchoi varieties for cultivation during summer in Zhejiang Province,several cultivation techniques are discussed in this dissertation regarding the issue of selecting and optimizing pakchoi varieties.Firstly,seven different pakchoi varieties are proposed for field experiments to screen out pakchoi varieties with best thermal adaptability and quality.Experimental results such as botanical character,yield,content of nutrition and nitrate content of harmful substance are investigated accordingly.Secondly,two pakchoi varieties with different levels of planting density are utilized to determine the reasonable planting density for growth of the pakchoi based on its botanical character in Zhejiang Province.For the third,various kinds of sunshade nets are implemented in field experiments of two pakchoi varieties.Proper kinds of sunshade nets are determined on a basis of variations in quality index of pakchoi varieties,which can be suggested for large-scale cultivation of pakchoi in Zhejiang Province.Analysis results of the field experiments above provide guidance for cultivation of pakchoi varieties in Zhejiang Province.Such analysis results are as follows.1.Analysis results are derived from fuzzy evaluation of seven pakchoi varieties,which demonstrate that ’ Ri Ben Hua Guan’,’Jin Pin 104’ and ’Xia Di’ grow with better thermal adaptability during summer in Zhejiang Province.Moreover,experimental results of content of nutrition and content of nitrate show that Vitamin C,soluble sugar and content of nitrate of ’Xia Di’is usually higher among the seven pakchoi varieties,and content of nitron in leaf of ’Jin Pin 21’ is the highest of all.Besides,results taste tests reveal that ’Ri Ben Hua Guan’,’Jin Pin 104’ and ’Xia Lv’ are with good flavor.Above all,relationship between results of taste tests and botanical character,content of nutrition or content of nitrate is investigated.Corresponding results indicate that there is a postive correlation between flavor of certain pakchoi variety and plant weight or leaf width,a negative correlation between flavor of certain pakchoi variety and content of nitrate or content of cellulose,and no significant correlation between flavor of certain pakchoi variety and other botanical character or quality index.2.Analysis results of field experiment indicate that plant hiegiht,leaf length,petiole length,leaf width,leaf number and plant weight decreases significantly with the increase of planting density,in each picking time.Specifically,planting density impacts growth of pakchoi in certain pattern.Meanwhile,when pakchoi is planted with planting density of 100 plants/m2,the yield of pakchoi reaches a peak value,and the yield of pakchoi decreases if pakchoi is planted with a greater planting density.Therefore,pakchoi is suggested to be planted with seeding density of 100 plants/m2.3.Sunshade nets are made of different materials,which have major impacts on growth and botanical character.Experimental results show that the mulching of plastic film,insect-proof,silver gray sunshade nets or black sunshade nets results in attenuation of light,decreases of environmental temperature and soil temperature.As a result,strong light stress is almost removed in field experiment with mulching of sunshade nets and such.Additionally,different options of sunshade nets affect growth of pakchoi in different ways,mainly in increase of plant height,plant expansion and leaf number.In general,according to the analysis results of content of nutrition and content of nitrate,content of Vitamin C and cellulose is lower and content of nitrate is higher in pakchoi with sunshade nets thant that in pakchoi without sunshade nets.更多还原