水杨酸对不同灌水下限青花菜生理特性及产量品质的影响

以青花菜为试材,采用大田试验研究了0.15mmol/L水杨酸(SA)对不同灌水下限(75%、60%和45%土壤相对含水量)青花菜生理特性及产量品质的影响。结果显示:(1)随灌水下限的降低,青花菜叶片相对含水量、水势及叶绿素含量均呈下降趋势,而其叶片电解质渗透率以及游离脯氨酸(Pro)、丙二醛(MDA)、可溶性蛋白(Pr)含量逐渐升高;青花菜的花球重及维生素C含量(Vc)随灌水下限的降低而降低,相反硝酸盐含量及可溶性固形物含量随之升高。(2)叶面喷施0.15mmol/L SA显著提高了青花菜叶片相对含水量、水势、渗透调节物质含量、产量及品质,且降低了膜脂过氧化产物MDA含量,其中以45%灌水下限处理效果最为显著,60%灌水下限处理次之,75%灌水下限处理最小。研究认为,适宜浓度外源SA通过改善青花菜叶片水分生理状况,提高叶片渗透调节物质含量,降低质膜透性来增强其对干旱胁迫的抗性,且以60%灌水下限配合叶面喷施0.15mmol/L SA处理较佳。     

Effects of different host plants and rearing atmosphere on life cycle of large white cabbage butterfly,Pieris brassicae (Linnaeus)

We studied the effect of different host plants and rearing atmosphere on life cycle of cabbage butterfly, Pieris brassicae. Insects were reared in the field (fluctuating weather) as well as in the laboratory (constant rearing conditions) on four host plants, viz. cabbage, cauliflower, knol-khol and broccoli. Significant differences were not found in the incubation and pupal period of butterfly reared on different host plants. However, larval period was found to be significantly lower on cabbage followed by knol-khol and highest on broccoli. Therefore, the developmental period (from eggs to adult) was reasonably lower on cabbage. Furthermore, inverse relationship was found in the body weight of butterfly and developmental period, where weight of full grown caterpillar and pupae was significantly higher on cauliflower and lowest on cabbage. Besides, significant differences were not found in the body weight of P. brassicae caterpillar reared under field and in the laboratory. Nevertheless, pupal weight of butterfly was significantly higher under field conditions than the laboratory conditions. Overall, the development of P. brassicae was much faster on cabbage than other hosts; but its body weight was considerably higher on cauliflower.     

Translocation and effectiveness of foliar-fertilized boron in broccoli plants of varying boron status

The translocation and effectiveness of foliar-fertiilized boron (B) was investigated in broccoli plants supplied via the root system with luxury, sufficient or deficient levels of B. ¹⁰B-enriched boric acid was applied three times to lower leaves, beginning one week prior to inflorescence emergence, and the shoot and floret yields, as well as the ¹⁰B and ¹¹B contents or concentrations of xylem sap, phloem exudate and various plant parts, were determined three weeks after inflorescence emergence. The amount of ¹⁰B translocated in phloem from fed leaves to the remainder of the shoot did not exceed 0.5%, of that supplied, but it was inversely related to plant-B status. The partitioning of translocated ¹⁰B to florets (16–30%) and the degree of enhancement in floret yield (28–75%) was also inversely related to plant-B status. It is concluded that foliar-B fertilization may be more effective for preventing B deficiency than soil-derived B in leaves.Abbreviations ¹⁰B/¹¹B mass isotopes of boron - DM dry matter - FF foliar fertilization - RF root fertilization     

Sucrose supply can increase longevity of broccoli (Brassica oleracea) branchlets kept at 22°C

Sucrose was supplied several hours after harvest to broccoli branchlets via the transpiration stream in order to increase the amount of sucrose available for respiration and to determine its influence on longevity at 22°C. Calculations based on solution uptake indicated that an 8% (w/v) sucrose solution supplied sufficient substrate for respiration, but the pattern of respiratory decline after harvest was not altered by supply of exogenous sucrose, and yellowing of floret sepals began after 2 days. However, when sucrose was supplied immediately after harvest, yellowing was delayed. Treatment with cytokinin (50 ppm 6-benzylaminopurine), to delay yellowing, had no effect on levels of sucrose in branchlets after 4.5 days, but retarded loss of chlorophyll. Floret tissues appear to sense the decline in sucrose after harvest, the result being induction of senescence as judged by yellowing. 6-benzylaminopurine may block the sensing mechanism.Abbreviations BAP 6-benzylaminopurine     

Mechanism for proliferation inhibition by various selenium compounds and selenium-enriched broccoli extract in rat glial cells

The objective of this study was to investigate the differential effects of various selenium (Se) compounds and Se-enriched broccoli extracts on cell proliferation and the possible mechanism responsible for the Se-induced growth inhibition. C6 rat glial cells were incubated with graded concentrations up to 1000 nM of selenite, selenate, selenomethionine (SeM), Se-methyl-selenocysteine (SeMCys), high-Se broccoli (H-SeB) extract or low-Se broccoli (L-SeB) extract for 24 and 48 h. MTT results indicated that all Se sources and levels examined inhibited C6 cell proliferation at 48 h. The results from cell cycle progression and apoptosis analysis indicated that SeM, SeMCys, H-SeB or L-SeB treatments at the concentration of 1000 nM reduced the cell population in G₀/G₁ phase, but induced G₂/M phase arrest and increased apoptosis and secondary necrosis in C6 cells at 24 h. The populations of apoptotic cells and secondary necrotic cells were increased by all Se sources examined. The COMET assay indicated that there was no significant DNA single-strand break found for all Se treatments in C6 cells for 48 h. In addition, the Se-induced proliferation inhibition may involve a hydrogen peroxide (H₂O₂)-dependent mechanism with elevated cellular glutathione peroxidase (cGPX) activity. Both H-SeB and L-SeB inhibited C6 cell proliferation but H-SeB was less inhibitory than L-SeB. The proliferation inhibition by H-SeB in C6 cells is apparently related to the increased H₂O₂ with the elevated cGPX activity, but the inhibition by L-SeB was H₂O₂-independent without change in cGPX activity.     

同源四倍体青花菜的核型分析

以四倍体青花菜为材料,采用常规压片法进行核型分析和有丝分裂观察.结果表明:四倍体青花菜核型公式为2n=4x=36=16m+20sm(4 SAT),其中第3、4、7、8对为中着丝粒染色体,第1、2、5、6、9对为近中着丝粒染色体,第6对染色体具随体;核型类型属于2A型,为基本对称型;染色体相对长度组成为2n=36=16 M_2+20 M_1,表明该四倍体青花菜是二倍体加倍得到,为同源四倍体.在部分四倍体根尖中发现非整倍体细胞,其染色体数目变异较大;与二倍体相比,四倍体有丝分裂过程存在双核仁、体细胞配对、染色体桥等异常现象.     

Bioavailability of selenium from meat and broccoli as determined by retention and distribution of 75Se

The concentration of selenium (Se), an essential nutrient, is variable in foods, depending, in part, on how and where foods are produced; some foods accumulate substantial amounts of Se when produced on high-Se soils. The chemical form of Se also differs among foods. Broccoli is a Se-accumulating plant that contains many methylated forms of Se, and Se bioavailability from broccoli has been reported to be low. Red meats such as pork or beef could accumulate Se when the animal is fed high-Se diets, and Se from such meats has been reported to be highly bioavailable for selenoprotein synthesis. In a further attempt to characterize the utilization of Se from broccoli and meats such as pork or beef, we have fed rats diets adequate (0.1 μg Se/g diet) in Se or high in Se (1.5 μg S/g diet), with the Se source being either high-Se broccoli or beef. Rats were then given test meals of broccoli or pork intrinsically labeled with ⁷⁵Se. When dietary Se was nutritionally adequate (0.1 μg/g diet), more ⁷⁵Se from pork than broccoli was retained in tissues; however, there were no significant differences in whole-body retention when dietary Se was high (1.5 μg/g diet). A significantly greater percentage of ⁷⁵Se from broccoli than pork was excreted in the urine and dietary Se did not affect urinary excretion of broccoli ⁷⁵Se, but the amount excreted from pork varied directly with dietary Se intake. Radiolabeled ⁷⁵Se derived from pork effectively labeled selenoproteins in all tissues examined, but ⁷⁵Se from broccoli was undetectable in selenoproteins. These differences in retention and distribution of Se from broccoli or pork are consistent with reported differences in bioavailability of Se from beef and broccoli. They also suggest that there are fewer differences in bioavailability when Se is consumed in supranutritional amounts.     

青花菜Ogu不育胞质分子鉴定和序列分析

雄性不育是农作物利用杂种优势、进行轮回选择和群体改良的重要手段,在农作物生产中具有巨大的利用价值。该研究为了鉴定青花菜细胞质雄性不育材料的不育胞质类型,以期今后为青花菜种质资源的收集、利用及分子标记辅助育种提供新的不育标记。根据Gen Bank中orf138基因保守序列设计特异引物,对20个青花菜种质资源基因组DNA进行PCR扩增。结果表明:特异引物P1/P2在12个青花菜雄性不育基因型中均扩增出392 bp的片段,在8个可育基因型中未扩增出条带,与田间育性鉴定结果相符。获得青花菜Ogu胞质雄性不育的特异基因orf138序列,Gen Bank中的登录号为HQ149728;用Blastn在Gen Bank中进行同源性比对分析,发现12个不育材料的特异片段与已报道的萝卜Ogu CMS所具有的Ogu orf138基因(Genbank登录号:Z18896.1)同源度高达100%。序列同源比对发现orf138基因存在变异位点。研究结果可为青花菜雄性不育细胞质的分子鉴定、进一步阐明胞质雄性不育败育机理,以及指导青花菜新型不育系的创建和杂种优势高效利用提供理论依据。     

青花菜细胞质雄性不育相关miRNA的鉴定与表达特征分析

植物miRNA是一类内源小分子RNA,在花粉发育和育性调控中具有重要作用。该研究利用高通量测序技术构建了青花菜细胞质雄性不育系及其保持系花蕾的sRNA文库,并通过qRT PCR技术检测育性相关的miRNAs及其预测靶基因的表达特征,为深入探讨miRNA调控青花菜育性机制提供理论依据。结果表明：(1)在青花菜中共鉴定到181个保守miRNA和8个新型miRNA,差异表达miRNA共47个,其中24个已知miRNAs和4个新型miRNAs表达上调,其余为表达下调;发现2个差异miRNA只在不育系中表达,7个差异miRNA为保持系所特有。(2)生物信息学分析表明,共鉴定到2个关联的miRNA mRNA对［miR859 1靶向的花粉外壁蛋白基因(T2/Unigene_BMK.21608)和miR5174e 1调控的氨基酸通透酶基因(T2_Unigene_BMK.31772)］,2个miRNA均负向调控相应的靶基因,均可参与青花菜小孢子发育以及雄性不育的发生过程。(3)qRT PCR分析显示,miR159a 1、miR164a 1、miR319a 1和miRn11在青花菜不育系中的表达量高于其保持系,其中miR164a 1、miR319a 1和miRn11的表达水平随着花蕾的发育不育系逐渐降低,而在保持系的表达呈上升趋势;miR319a 1和miR397a 2在雄蕊中的表达量高,而在其他部位的表达量较低,且miR397a 2在青花菜不育系中的表达量显著低于保持系。研究推测,miRNA可能是通过抑制雄性不育相关的PPR基因表达、调控LAC基因的表达以及调节激素和Ca²⁺介导的信号转导通路等,从而导致青花菜雄性不育的发生。     

Broccoli Stunt,a New Disease in Broccoli Plants Associated with Three Distinct Phytoplasma Groups in Brazil

Since 2007, a new disease in broccoli (Brassica oleracea var. italica Plenck) has been observed in the São Paulo state, Brazil. The characteristic symptoms of the disease are plant stunting, inflorescence malformation, reddening of the leaves and phloem necrosis. Nested polymerase chain reaction with P1/Tint and F2n/R2 primer pairs revealed the presence of phytoplasmas in diseased broccoli plants. Restriction fragment length polymorphism and phylogenetic analysis of the 16S rDNA gene showed that phytoplasmas belonging to 16SrI, III and XIII groups were associated with the plants. To the best of our knowledge, this is the first report of phytoplasmas in this Brassica species in Brazil, as well the first time phytoplasmas of 16SrIII and XIII groups have been associated with broccoli plants.