【作者】 周俊国；

【导师】 朱月林；

【作者基本信息】 南京农业大学 ， 蔬菜学， 2008， 博士

【摘要】 设施栽培中由于多年连作和不合理施肥,土壤次生盐渍化严重,严重影响到保护地蔬菜生产的产量和品质。瓜类是我国设施栽培的主要蔬菜,利用耐盐砧木对瓜类实施嫁接栽培是一条合理利用次生盐渍化土壤的有效措施。南瓜是瓜类嫁接栽培中的主要砧木,尤其是黄瓜的主要砧木,具有根系发达、亲合性好、抗土传病害的砧木特点,中国南瓜（Cucurbita moschata Duch.）是南瓜属的一个种,适应性广,抗逆性强,我国有丰富的资源,从中选择耐盐的瓜类砧木材料具有可能,但目前仍没有专用的耐盐瓜类砧木在生产上使用。关于中国南瓜耐盐生理特性的研究也较少,只限于种子发芽和幼苗期的一些耐盐生理研究。本研究以中国南瓜F₁杂种为试验材料,从中筛选出较耐盐的‘360-3×112-2’F₁杂种,用瓜类嫁接生产中应用较普遍的砧木‘黑籽南瓜’（C.ficifolia Bouche.）作参照,比较研究了中国南瓜‘360-3×112-2’F₁杂种耐盐砧木的耐盐生理特性,并通过嫁接研究了‘360-3×112-2’F₁杂种作为砧木利用的可能性。1.在组培条件下以中国南瓜为试验材料,采用不同浓度的NaCl处理中国南瓜幼苗,研究了NaCl胁迫对中国南瓜自交系和F₁杂种幼苗的生长抑制率、盐害指数和半致死盐浓度。试验结果表明,自交系幼苗在120 mmol·L^-1 NaCl浓度处理下生长受到严重抑制,而F₁杂种幼苗在160 mmol·L^-1 NaCl浓度处理下生长才受到严重抑制。中国南瓜F₁杂种的耐盐性比其自交系的耐盐性强,中国南瓜的耐盐性具有杂种优势。中国南瓜F₁杂种幼苗在120 mmol·L^-1 NaCl浓度处理下存在明显的耐盐性差异,69份F₁杂种的幼苗在120 mmol·L^-1 NaCl浓度处理下的盐害指数介于29.94～100之间,呈正态分布,有6份F₁杂种表现出较高的耐盐性,其中‘360-3×112-2’F₁杂种耐盐性最强。提出在组培条件下采用120 mmol·L^-1 NaCl浓度处理中国南瓜幼苗,可以有效地筛选耐盐材料。2.在组织培养条件下,对中国南瓜‘360-3×112-2’F₁杂种和‘黑籽南瓜’的幼苗分别进行不同NaCl浓度胁迫处理,结果表明,‘360-3×112-2’F₁杂种和‘黑籽南瓜’在幼苗期存在明显的耐盐性差异,‘360-3×112-2’F₁杂种耐盐性比‘黑籽南瓜’强,前者的最高耐盐浓度是160 mmol·L^-1,后者的最高耐盐浓度是120 mmol·L^-1。3.营养液栽培条件下,在成株期以80 mmol·L^-1 NaCl胁迫中国南瓜‘360-3×112-2’F₁杂种和‘黑籽南瓜’植株,10d后,测定了植株的生长量和不同器官中Na⁺、K⁺、Ca²⁺、Mg²⁺的含量,结果表明NaCl胁迫后两种南瓜植株体内Na⁺含量升高,‘360-3×112-2’F₁杂种的Na⁺主要累积在根部,‘黑籽南瓜’主要积累在茎中;K⁺、Ca²⁺、Mg²⁺的含量在植株体内呈下降的趋势,但‘360-3×112-2’F₁杂种的上位叶中的含量却上升;NaCl胁迫下因Na⁺的积累抑制了K⁺的吸收,植株各器官的K⁺/Na⁺普遍降低,但‘黑籽南瓜’比‘360-3×112-2’F₁杂种的K⁺/Na⁺下降明显。这些结果说明,两种南瓜受到盐胁迫后Na⁺的主要积累器官不同,致使地上部各器官有不同的K⁺、Ca²⁺、Mg²⁺吸收和积累特性,K⁺/Na⁺降低幅度也不同,从而影响了植株的生长,产生了耐盐性的差异。4.在营养液栽培条件下研究了在成株期以80 mmol·L^-1 NaCl胁迫10d对中国南瓜‘360-3×112-2’F₁杂种和‘黑籽南瓜’植株生长和根系生理特征的影响。结果表明:NaCl胁迫对两种材料的生长有不同程度抑制,其中功能叶单叶面积受抑制程度最大,‘黑籽南瓜’所受抑制更强。NaCl处理能显著提高‘360-3×112-2’F₁杂种的根系活力,却对‘黑籽南瓜’植株根系活力有显著抑制作用。随NaCl胁迫延续,两种材料根系中可溶性糖和脯氨酸含量均呈现先上升后下降的规律,‘360-3×112-2’F₁杂种植株的2种渗透物质上升幅度较大而下降的幅度较小且始终显著高于同期‘黑籽南瓜’。两种材料根系O₂^-产生速率随胁迫延续逐渐上升,但‘360-3×112-2’F₁杂种上升幅度渐减小,而‘黑籽南瓜’上升幅度持续增加;‘360-3×112-2’F₁杂种根系中MDA含量先升后降,‘黑籽南瓜’的MDA含量持续上升;NaCl胁迫使两种材料根系抗氧化酶活性均有不同程度增加,SOD和CAT活性先升后降,POD活性则持续升高,但‘360-3×112-2’F₁杂种的上述酶活性增幅均大于同时期‘黑籽南瓜’。以上结果表明,成株期的中国南瓜‘360-3×112-2’F₁杂种在NaCl胁迫下生长抑制率较低,根系活力较强,具有较强的渗透调节能力和调节活性氧平衡能力,耐盐性比‘黑籽南瓜’强。5.在营养液栽培条件下研究80 mmol·L^-1 NaCl胁迫10d对成株期的中国南瓜‘360-3×112-2’F₁杂种和‘黑籽南瓜’植株生长、根系活性氧水平和游离态多胺含量的影响。结果表明,NaCl胁迫10 d,中国南瓜‘360-3×112-2’F₁杂种和‘黑籽南瓜’植株生长受到抑制,‘360-3×112-2’F₁杂种比‘黑籽南瓜’植株耐盐。NaCl胁迫后南瓜根系O₂^-产生速率和H₂O₂含量提高,‘黑籽南瓜’的O₂^-产生速率和H₂O₂含量高于‘360-3×112-2’F₁杂种。南瓜根系中腐胺（Put）、亚精胺（Spd）、精胺（Spm）和多胺（Pas）含量及Put/PAs值高于对照,呈现先升高后下降的趋势;根系中（Spd+Spm）/Put值低于对照,呈现先下降后升高的趋势。‘360-3×112-2’F₁杂种根系中Put含量和Put/PAs值低于‘黑籽南瓜’,而Spd、Spm含量和（Spd+Spm）/Put值高于‘黑籽南瓜’;分析认为,两种南瓜根系中多胺含量的升高对减少或清除组织中的ROS有积极的作用,Put向Spd、Spm转化有利于增强植株的耐盐性。‘360-3×112-2’F₁杂种的耐盐性高于‘黑籽南瓜’与根系中Put/PAs值较低、（Spd+Spm）/Put值和PAs含量较高、清除活性氧能力较强有关。6.用前期试验筛选出的较耐盐的中国南瓜‘360-3×112-2’、‘077-2×112-2’、‘360-3×635-1’F₁杂种为试验砧木,以生产上常用的黄瓜砧木‘黑籽南瓜’作对照,以‘津春2号’黄瓜为接穗,用靠接法和插接法在温室营养钵育苗条件下,研究中国南瓜F₁杂种作为黄瓜砧木的嫁接亲合性和对嫁接苗生长的影响。结果表明,中国南瓜F₁杂种幼苗下胚轴细而高,嫁接成活率比‘黑籽南瓜’低,插接法嫁接成活率优于靠接法。但嫁接20d后‘360-3×112-2’和‘360-3×635-1’F₁杂种作砧木的嫁接苗单株叶片数、最大叶片面积、根系和地上部鲜重不低于‘黑籽南瓜’嫁接苗,具备作为黄瓜砧木的基本条件,其中‘360-3×112-2’F₁杂种的嫁接苗根冠比较高,幼苗健壮,而‘077-2×112-2’F₁杂种作为砧木嫁接成活率较低,生长指标较差,不宜作黄瓜砧木。更多还原

【Abstract】 Due to the continuous cultivation and unreasonable fertilization in protected cultivation soil,the secondary salinization soil has become a very serious problem, resulting in a serious reduction of yield and quality of vegetable protection production. Cucurbits are one of the main vegetable species in protected cultivation.It is showed that cucurbits grafting cultivation using salt-tolerant rootstock is an effective measure to utilize the secondary salinization soil reasonable.Pumpkin is the main rootstock species of grafted cucurbits production,which have some features such as well developed roots,good compatibility,resistance soil-borne diseases.Cucurbita moschata is a cultivated species of Cucurbita,which have extensive adaptability,strong stress resistance,abundant germplasm resources in China.It is reasonable that screening salt-tolerant cucurbits rootstock from C. moschata,however,special salt-tolerant rootstock were not used in cucurbits production. Less physiological characteristics of salt-tolerant on C.moschata was studied,these are only in salt-toleran physiological of germination period and seedling stage.We use C. moschata hybrids as trial material,and screening salt-tolerant hybrid,and then using C. ficifolia,widely used in grafted cucumber production as a control,comparisons of salt-tolerant physiological were made between salt-tolerant hybrid and C.ficifolia in their adult stages.1.In vitro comparison of the salt tolerance of C.moschata were made at the seedling stage exposed to a series of NaCl concentration.The results showed that hybrids are stronger than their inbred lines in salt tolerance,there is heterosis about salt tolerance of C. moschata.The growth of 3 inbred lines and 6 hybrids seedlings were inhibited seriously under MS medium supplemented with 120 and 160 mmol·L^-1 NaCl respectively.There were significant differences in salt tolerance among 10 tested materials with 6 salinities(0, 40,80,120,160,200 mmol·L^-1).The salt injury index（SII） of seedlings of 69 pumpkin hybrids ranged from 29.94 to 100 and the frequency distribution was normal by normal test. Salt-tolerant hybrids of 6 were obtained,of which ’360-3×112-2’ showed the strongest salt tolerance.120 mmol·L^-1 NaCl was determined as an effective concentration to select salt-tolerant materials from pumpkin hybrid seedlings.2.In vitro comparison of the salt tolerance of C.ficifolia and C.moschata hybrid of ’360-3×112-2’ which showed stronger salt tolerance with previously selected experimental result,were made at the seedling stage exposed to a series of NaCl concentration(0、40、80、120、160、200 mmol·L^-1).The results showed that obvious difference in salt tolerance was exited between C.moschata hybrid of ’360-3×112-2’ and C.ficifolia,and the salt tolerance of the former was significantly higher than the later.It was suggested that 160 mmol·L^-1 and 120 mmol·L^-1 NaCl were the maximum stress value that C.moschata hybrid of ’360-3×112-2’ and C.ficifolia could tolerate respectively.Those results make hybrid of ’360-3×112-2’ available in breeding of salt-tolerant rootstock.3.To compare ’360-3×112-2’hybrid of salt tolerance with C.ficifolia,both of them were cultured in nutrient solution added with 0 mmol·L^-1 or 80 mmol·L^-1 NaCl in adult plant period.After 10 days,the growth traits and the contents of Na⁺,K⁺,Ca²⁺ and Mg²⁺ in six organs including root,stem,petiole,upper leaf,middle leaf and lower leaf of all plants were determined.Results showed that growth inhibition of two tested plants was obvious under NaCl stress for 10 days,growth of ’360-3×112-2’ hybrid plants was less inhibited than that of C.ficifolia Bouche.Na⁺ contents in six organs of two tested materials were all increased,Na⁺ contents of ’360-3×112-2’ hybrid mainly accumulated in roots,while C. ficifolia Bouche.in stem.K⁺,Ca²⁺ and Mg²⁺ contents generally decreased in plant,however, increased in upper leaf of’360-3×112-2’ hybrid.Although K⁺/Na⁺ values in all organs were decreased under NaCl stress,’360-3×112-2’ hybrid decreased less than C.ficifolia Bouche. Therefore,difference in organs accumulating high Na⁺ contents,and difference in K⁺,Ca²⁺, Mg²⁺ contents and K⁺/Na⁺ decrease range in shoot were the main reasons for the differences of salt tolerance between the two tested materials under NaCl stress after 10 days.4.To evaluate the salt tolerance of ’360-3×112-2’ hybrid at adult plant stage（with 10 leaves）,the roots physiological and biochemical characteristics and plants growth were further studied comparing with C.ficifolia under NaCl stress in condition of solute culture. The results showed:（1） NaCl stress had lower inhibitory effect on the plants growth of hybrid which reflected in the reduction of fresh weight of roots and shoots,length of main stem,number of functional leaves,especially in individual areas of the youngest functional leaves comparing with C.ficifolia based on the investigation data at 9 day after NaCl treatment（DAT）.（2） NaCl treatment could promote the roots vigor of ’360-3×112-2’ hybrid and inhibit that of C.ficifolia significantly.（3） Although the two osmoregulatory substances in roots of two tested materials had peak value in the first day of NaCl stress and appeared similar change tendency which rose first and fell later,the hybrid were always higher than C.ficifolia.The rising range of soluble sugar and proline in earlier phase were more obvious than the descend range in later stress time in hybrid.（4） O₂^-production rate of two test material roots gradually increased,but the rising range of O₂^-production rate of hybrid became lower than that of C.ficifolia with NaCl stress.Content of MDA of hybrid roots was raised firstly then dropped,yet that of C.ficifolia increased gradually.（5） Activity of SOD,POD and CAT of two material roots were increased under NaCl stress,and SOD and CAT raised firstly then dropped,POD increased continuous,the range of increase of 3 antioxidase of ’360-3×112-2’ hybrid roots at same stress time were higher than that of C.ficifolia roots.Those results indicated that ’360-3×112-2’ hybrid plants had lower growth inhibition rate,higher roots vigor,better osmotic adjustment ability and regulation balance of active oxygen under NaCl stress at adult plant stage.The comparing research also concluded that ’360-3×112-2’ hybrid has higher tolerance to NaCl stress than C.ficifolia.5.Plant growth,O₂^-production rate,H₂O₂ content and contents of free polyamines （PAs） includ free putrescine（Put）,Spermidine（Spd）,Spermine（Spin） in the roots of Cucuibita moschata Duch.hybrid and C.ficifolia which differing in salt sensitivity at adult plant stage（10 leavies） were investigated under 80 mmol·L^-1 NaCl stress in hydroponic for 10 days.The results showed that salt injuries and growth inhibition occurred both in tested plants after 10d stress,and that of C.ficifolia Bouche were much more serious than ’360-3×112-2’ hybrid.During NaCl stress,O₂^-production rate and H₂O₂ content in ’360-3×112-2’ hybrid were increased similar to C.ficifolia Bouche.,yet absolute values were lower than that of the latter.Contents of Put,Spd,Spm,PAs and Put/PAs value on two test material roots were always higher than control,rised first and fall later,while （Spd+Spm）/Put value were lower than control,decreased firstly and then increased. Compared with C.ficifolia Bouche.,Put/PAs value and Put content in ’360-3×112-2’ hybrid roots were always lower,while（Spd+Spm）/Put value and contents of Spd and Spm were always higher.It was concluded that increasing PAs content levels in two pumpkin roots played an active role on decreasing or scavenging ROS under NaCl stress.The conversion of Put to Spd and Spin was advantageous to the increase of plant salt tolerance. The higher salt tolerance of ’360-3×112-2’ than C.ficifolia Bouche.was closely related to its some physiological characteristics in roots,such as the lower Put/PAs value,the higher （Spd+Spm）/Put value and PAs content,the stronger the capacity to scavenge active oxygen species.6.The compatibility and grafted seedling growth of different C.moschata hybrids （’360-3×112-2’、’077-2×112-2’、’360-3×635-1’） and C.ficifolia rootstocks on cucumber cultivar of ’Jinchun 2’ were studied by approach grafting and sprout insertion grafting using pot cultivation in greenhouse.the results showed that 3 C.moschata hybrids rootstocks were compatible with ’JinChun 2’ cucumber cultivar,but with lower survival rates than C. ficifolia rootstocks,differences in hypocotyls diameter and height between C.moschata hybrids and C.ficifolia rootstocks reduced the survival ratio of grafts,while with higher survival ratio of grafts by sprout insertion grafting than approach grafting.’360-3×112-2’ and ’360-3×635-1’ hybrids have the basic conditions of cucumber rootstock for their average leaves number,the largest leaf area,the fresh weight of roots and tops of grafted seedling no less than that of C.ficifolia rootstocks after grafting 20 days.And ’360-3×112-2’ hybrid is recommended as a cucumber rootstock for it’s stronger grafted seedling with higher root-top ratio,but ’077-2×112-2’ hybrid is not recommended for it’s the lower grafting survival rates and poor growth vigor.更多还原