西藏和周边地区芥菜型油菜农艺性状比较研究

利用113份芥菜型油菜,运用典范相关分析方法,对西藏及周边地区芥菜型油菜的产量性状、主茎性状、分枝性状、角果性状等4组性状间的典范相关关系进行了比较研究。结果表明：(1)所研究的18个性状中,西藏芥菜型油菜的均值为周边地区芥菜型油菜的1.88倍,总体变异系数比周边省份芥菜型油菜高10.22%;(2)西藏芥菜型油菜单株产量主要取决于每株角果数和千粒重,而周边省份芥菜型油菜单株产量主要取决于每株有效角果数,中国周边国家芥菜型油菜单株产量主要取决于每株有效角果数、千粒重;(3)影响西藏芥菜型油菜产量性状最重要的因素是角果性状,其次是分枝性状和主茎性状,而影响周边省份和中国周边国家芥菜型油菜产量性状最重要的因素则是主茎性状,其次是分枝性状和角果性状;(4)西藏芥菜型油菜4组性状间极显著或显著相关的典型变量累计有9对性状,周边省份芥菜型油菜有8对性状,中国周边国家芥菜型油菜有5对性状,西藏与周边省份和中国周边国家芥菜型油菜生态性状间既有密切联系,亦略不同。     

Use of Brassicaceous seed meals to improve seedling emergence of tomato and pepper in Pythium ultimum infested soils

Growth room studies were conducted to determine the impact of Brassicaceae seed meals on the emergence of tomato and pepper seedlings in Pythium ultimum infested soils. Pasteurised Burch sandy loam soils were amended with intact and denatured seed meal of rape seed and mustard. Brassica juncea or Brassica napus intact seed meal increased the tomato and pepper seedling emergence. Interestingly, B. napus amended soils resulted in the same seedling emergence with B. juncea regardless of their relatively lower glucosinolate content compared to mustard-based seed meals. Seedling emergence in soils amended with intact Sinapis alba seed meal was significantly the lowest for both tomato and pepper seedlings. In contrast, seedling emergence was higher in soils amended with denatured than intact S. alba seed meals suggesting some glucosinolate-related inhibitory effect on seedling emergence of both crops. Glycine max seed meal amendment improved the seedling emergence better than the control but to a lower-level when compared to glucosinolate containing seed meals. This finding suggests that even though improvement of seedling emergence of tomato and pepper in P. ultimum infested soils can be achieved using Brassicaceae seed meals, it cannot be entirely attributed to glucosinolate-related processes. These studies demonstrate that intact B. napus and B. juncea seed meals can be used to improve tomato and pepper seedling emergence in P. ultimum infested soils.     

芥菜HDA9突变体构建及其与开花整合子SOC1、AGL24启动子互作

芥菜HDA9是去乙酰化酶家族成员,能通过开花信号整合子(SOC1、AGL24)调控开花时间,但其深入的分子调控机制仍不清楚。利用重叠延伸PCR将芥菜HDA9的3个关键活性位点(Asp~(172)、His~(174)和Asp~(261))分别突变为Ala,构建氨基酸位点突变体HDA9~(D172A)、HDA9~(H174A)和HDA9~(D261A)。进一步将突变体融合到pGADT7载体,酵母单杂交表明,HDA9突变后仍能与开花整合子SOC1、AGL24的启动子结合。双荧光素酶系统深入检测发现,尽管HDA9~(D172A)、HDA9~(H174A)和HDA9~(D261A)与SOC1、AGL24启动子的结合仍存在,但作用强度均显著减弱。由此暗示,芥菜HDA9的第172、174和261这3个关键活性位点可在一定程度上调节它与开花整合子的相互作用。这为HDA9开花分子调控及功能解析等深入研究奠定了基础。     

豇豆胰蛋白酶抑制剂基因转化芥菜及抗虫鉴定

用农杆菌介导将豇豆胰蛋白酶抑制剂 (CpTI)基因导入芥菜 ,获得了Kan抗性植株 .经PCR扩增、PCR Southern印迹和Northern印迹分析 ,转化再生植株大部分呈阳性 ,而非转化的再生植株均为阴性 ,证明CpTI基因已存在于芥菜基因组中 .在室内进行了喂虫试验 ,结果表明转基因芥菜抗虫性明显高于对照 ,转基因植株之间存在抗虫性差异     

芥菜型油菜与埃塞俄比亚芥杂种基因组原位杂交分析

原产于非洲的埃塞俄比亚芥(Brassica carinata,2n=34,BBCC)具有适应于炎热干旱地区种植等特点,是改良我国芥菜型油菜(B.juncea,2n=36,AABB)的重要种质资源。本研究用基因组原位杂交方法(GISH,Genomic in situ hybridization)分析了芥菜型油菜与埃塞俄比亚芥种间杂种花粉母细胞的染色体分离,发现在后期I染色体主要以17∶18类型分离,其次是16∶19,染色体落后现象偶然发生,其中B染色体组以8∶8的分离比率较高,表明不同来源的B染色体可正常配对分离。本研究表明,芥菜型油菜与埃塞俄比亚芥远缘杂交,通过染色体同源重组(B染色体间),以及部分同源染色体配对交换的方式(A、B、C基因组间),有可能将埃塞俄比亚芥优良遗传成分转移到芥菜型油菜中。     

大赖草及近缘物种原位杂交和Southern杂交的分析

用Ｔｈｉｎｏｐｙｒｕｍｂｅｓａｒａｂｉｃｕｍ（Ｓａｖｕｌ．＆Ｒａｙｓ）Ａ．Ｌｖｅ的基因组ＤＮＡ作探针,分别与大赖草Ｌｅｙｍｕｓｒａｃｅｍｏｓｕｓ（Ｌａｍ．）Ｔｚｖｅｌ．和脆轴偃麦草Ｔｈ．ｊｕｎｃｅｕｍ（Ｓａｖｕｌ．＆Ｒａｙｓ）Ａ．Ｌｖｅ的体细胞杂交,大赖草的１４对染色体均出现杂交信号,脆轴偃麦草只有７对染色体有杂交信号。在用重复ＤＮＡ序列ＰＨｖ６２作探针的原位杂交中,Ｔｈ．ｂｅｓａｒａｂｉｃｕｍ有４对染色体有杂交信号,大赖草有１３对染色体显示杂交信号,新麦草Ｐｓａｔｈｙｒｏｓｔａｃｈｙｓｊｕｎｃｅａ（Ｆｉｓｃｈ．）Ｎｅｖｓｋｉ和脆轴偃麦草无杂交信号。用ＰＨｖ６２作探针的Ｓｏｕｔｈｅｒｎ杂交结果与原位杂交相似。在被检测的１２个普通小麦大赖草异源染色体系中,除二体附加系中５Ｌｒ＃１和双二体附加系１Ｌｒ＃１＋５Ｌｒ＃１没有杂交信号外,其余的异染色体系与ＰＨｖ６２都有特异杂交信号。据此推测Ｔｈ．ｂｅｓａｒａｂｉｃｕｍ有可能参予了赖草属物种的形成过程。但是,大赖草的染色体组在进化过程中显然已发生过变异。     

The effects of rate and timing of N fertilizer on growth, photosynthesis, N accumulation and yield of mustard (Brassica juncea) subjected to defoliation

Mustard (Brassica juncea L.) is characterized by large number of broad oblong shaped leaves in the lower layers. Our earlier studies have shown that removal of these shaded lower leaves on mustard plant axis enhanced growth, photosynthetic capacity and yield of the crop. We now present evidence that soil-applied nitrogen (N) at pre- or post-flowering stage following defoliation of lower leaves influences plant growth, photosynthesis and assimilation balance. Following defoliation at pre-flowering, i.e. 40 d after sowing (DAS) and N applied at the rate of 100 kg ha⁻¹ at the time of sowing and 50 kg ha⁻¹ at post-flowering (60 DAS) enhanced the characteristics maximally. The defoliation treatment together with N combinations and the time of its application, N at 150 kg ha⁻¹ applied as single dose at the time of sowing or N applied in split; 100 kg ha⁻¹ at the time of sowing and 50 kg ha⁻¹ at 40 DAS or 75 kg ha⁻¹ at the time of sowing or 75 kg ha⁻¹ at pre- or post-flowering time proved less effective. The plants which were not defoliated and received 75 kg N ha⁻¹ at the time of sowing and 75 kg ha⁻¹ at 60 DAS showed lowest values. Furthermore, N assimilation was more efficient in plants following defoliation at 40 DAS. The results suggest that split N application (100 kg ha⁻¹ at sowing and 50 kg ha⁻¹ at post-flowering) enhances substantially growth, photosynthesis, N assimilation and yield of mustard following defoliation. This management practice could be adopted in mustard culture for increasing seed yield together with minimizing N loss.     

Identification of a flavin-monooxygenase as the S-oxygenating enzyme in aliphatic glucosinolate biosynthesis in Arabidopsis

The cancer-preventive activity of cruciferous vegetables is commonly attributed to isothiocyanates resulting from the breakdown of the natural products glucosinolates (GSLs). Sulforaphane, the isothiocyanate derived from 4-methylsulfinylbutyl GSL, is thought to be the major agent conferring cancer-preventive properties, whereas the isothiocyanate of 4-methylthiobutyl GSL does not have the same activity. We report the identification of an Arabidopsis flavin-monooxygenase (FMO) enzyme, FMO(GS-OX1), which catalyzes the conversion of methylthioalkyl GSLs into methylsulfinylalkyl GSLs. This is evidenced by biochemical characterization of the recombinant protein, and analyses of the GSL content in FMO(GS-OX1) overexpression lines and an FMO(GS-OX1) knock-out mutant of Arabidopsis. The FMO(GS-OX1) overexpression lines show almost complete conversion of methylthioalkyl into methylsulfinylalkyl GSLs, with an approximately fivefold increase in 4-methylsulfinylbutyl GSL in seeds. Identification of FMO(GS-OX1) provides a molecular tool for breeding of Brassica vegetable crops with increased levels of this important GSL, which has implications for production of functional foods enriched with the cancer-preventive sulforaphane.     

印度芥菜-苜蓿间作对镉胁迫的生态响应

采用温室盆栽试验,研究了重金属镉（Cd）胁迫对印度芥菜和苜蓿间作下的土壤-植物系统的影响,同时对苜蓿的Cd饲用安全进行了评估.结果表明：在土壤Cd含量为0.37～20.37 mg·kg^-1范围内,与单作印度芥菜和苜蓿相比,间作使印度芥菜生物量降低了0.4%～11.8%,而使苜蓿生物量提高了55.3%~70.0%.土壤有效Cd主要受土壤全量Cd和种植植物种类的影响,种植方式对其影响不大.在土壤Cd含量为5.37 mg·kg^-1时,间作印度芥菜地上部Cd含量较单作提高了14.5%,而间作苜蓿地上部Cd含量较单作降低了57.1%;此时,单作和间作苜蓿地上部Cd含量分别为0.21和0.09 mg·kg^-1,均未超过饲料卫生限定标准(0.5 mg·kg^-1).在土壤Cd含量为10.37～20.37 mg·kg^-1范围内,虽然单作和间作苜蓿Cd含量均超过饲料卫生限定标准,但间作种植方式仍然使苜蓿地上部Cd含量较单作降低了2.8%～48.3%,印度芥菜地上部Cd含量也较单作降低了1.1%～48.6%.不论单作还是间作印度芥菜的Cd转运系数都远高于苜蓿.