Formation of Pungent Principles in Fruits of Sweet Pepper,Capsicum annuum L. var. grossum during Post-harvest Ripening under Continuous Light

Pungent principles (Capsaicinoid(s)) were found to be produced in fruits of sweet pepper, Capsicum annuum L. var. grossum, during post-harvest ripening under continuous light. The initial formation was observed after 4 days’ ripening. After 7 days’ ripening, the capsaicinoids content in placenta increased to 12.9 μg per fruit, which was 2.5-fold of that in pericarp. No pungent principles were detected in fruits during ripening in the dark and in seeds under continuous light. In placenta, the formation of dihydrocapsaicin and nordihydrocapsaicin which are the vanillylamides of saturated branched fatty acids was higher than that of capsaicin which is the vanillylamide of an unsaturated one. Remarkable formation and accumulation of carotenoid were also observed during post-harvest ripening under continuous light.     

甜椒的离体培养及建立再生体系研究

以荷兰进口甜椒的子叶和下胚轴为外植体,接种到附加不同植物生长调节剂的培养基上,筛选出MS+6-BA 4.0 mg/L+NAA 0.1 mg/L为子叶和下胚轴最佳不定芽分化培养基;MS+IBA 0.2 mg/L和MS+IBA 0.5 mg/L为最佳不定根分化培养基。     

Tapetum Dimorphism and Its Histochemical Study in Sweet Pepper (Capsicum annuum L. Var. grossum)

In sweet pepper, the portion of tapetum toward the interior of the anther comprising large cells is derived from cells of connective of anther whereas the remaining tapetum on the outside of the anther comprising comparatively small cells is derived from the parietal layer. Those ceils of the former prosessing large vacuoles and large nuclei are stained weaker than the cells of the latter by methyl green-pyronin and mercuric-bromophenol blue staining. Large spherical grains which contain acid phosphatase appear in the vacuoles in both kinds of tapetum at sporogenesis stage. During meiosis of pollen mother cells, DNA, RNA and protein sysntheses increase in tapetum. The tapetum derived from connective accumulates more DNA than that derived from parietal layer. The activity of acid phosphatase becomes higher in tapetum when it degenerates. The degeneration of two kinds of tapetum is similar. There are no starch grains in tapetum through its whole course of development.     

In Vitro and in Vivo Melanogenesis Inhibition by Biochanin A from Trifolium pratense

Our previous study showed that a methanol extract from Trifolium pratense exerted potent inhibitory activity on melanogenesis in mouse B16 melanoma cells. In the present study, the active compound in this Chinese herb extract was isolated and identified as biochanin A by mass spectrum, ¹H-NMR, and ¹³C-NMR analysis. The inhibitory effects of biochanin A on melanogenesis were investigated in vitro in cultured melanoma cells and in vivo in zebrafish and mice. Biochanin A dose-dependently inhibited both melanogenesis and cellular tyrosinase activity in B16 cells and in zebrafish embryos. Application of a cream containing 2% biochanin A twice daily to the skin of mice also increased the skin-whitening index value after 1 week of treatment, and the increase continued for another 2 weeks. Biochanin A was confirmed as a good candidate for use as a skin-whitening agent in the treatment of skin hyperpigmentation disorders.     

辣椒离体培养及再生体系的研究

选用9个辣椒(Capsicum annuumL.)品种(系),研究了不同激素组合、基因型、外植体类型、苗龄和Ag-NO3等因素对外植体不定芽分化和伸长的影响.结果表明,在6-BA/IAA为10∶1配比下,有利于辣椒外植体的分化再生,而6-BA/IAA为3∶1配比下适合于再生芽的伸长;不同品种辣椒的再生能力差别较大,分化率在13.3%~90.0%之间;辣椒子叶再生能力比下胚轴强,是较好的外植体材料;12~16 d苗龄的外植体分化频率较高;添加4mg?L-1AgNO3可使芽分化率平均提高16.9%.通过比较,筛选出了适合于辣椒芽分化的培养基为MB5(MS无机盐 B5有机成分) 5 mg?L-16-BA 0.5 mg?L-1IAA 4 mg?L-1AgNO3,芽伸长培养基为MB5 3 mg?L-16-BA 1 mg?L-1IAA 2 mg?L-1GA3 4 mg?L-1AgNO3,生根培养基为1/2 MS 0.2 mg?L-1IAA 0.1 mg?L-1NAA.     

不同辣椒材料离体再生及其影响因素的研究

以8个辣椒(Capsicum annuumL.)纯系为材料,对不同材料、外植体种类和激素组合等因素对辣椒植株离体再生的影响进行了研究。结果表明,较高的6-BA/IAA值有利于辣椒外植体的分化再生,而6-BA/IAA值较低则适合于再生芽的伸长;不同辣椒材料的再生能力差别较大;辣椒带柄子叶再生能力比下胚轴强,是较好的外植体材料;12~16 d苗龄的外植体分化频率较高;在供试的8个辣椒材料中‘2096’、‘B4’和‘B7’的再生能力较强。高频率的不定芽分化培养基为MB(MS无机成分 B5有机成分) 0.8 mg/L IAA 5.0 mg/L 6-BA 4.0 mg/L Ag-NO3;不定芽伸长的培养基为MB 0.8 mg/L IAA 2.0 mg/L 6-BA 2.0 mg/L GA3 4.0 mg/L AgNO3;高效生根诱导培养基为MB 0.2 mg/L IAA 0.1 mg/L NAA。     

Evolution of Capsaicinoids in Peter Pepper (Capsicum annuum var. annuum) During Fruit Ripening

The evolution of individual and total contents of capsaicinoids present in Peter peppers (Capsicum annuum var. annuum) at different ripening stages has been studied. Plants were grown in a glasshouse and the new peppers were marked in a temporal space of ten days. The extraction of capsaicinoids was performed by ultrasound‐assisted extraction with MeOH. The capsaicinoids nordihydrocapsaicin (n‐DHC), capsaicin, dihydrocapsaicin, homocapsaicin, and homodihydrocapsaicin were analyzed by ultraperformance liquid chromatography (UHPLC)‐fluorescence and identified by UHPLC‐Q‐ToF‐MS. The results indicate that the total capsaicinoids increase in a linear manner from the first point of harvest at ten days (0.283 mg/g FW) up to 90 days, at which point they reach a concentration of 1.301 mg/g FW. The evolution as a percentage of the individual capsaicinoids showed the initial predominance of capsaicin, dihydrocapsaicin, and n‐DHC. Dihydrocapsaicin was the major capsaicinoid up to day 50 of maturation. After 50 days, capsaicin became the major capsaicinoid as the concentration of dihydrocapsaicin fell slightly. The time of harvest of Peter pepper based on the total capsaicinoids content should be performed as late as possible. In any case, harvesting should be performed before overripening of the fruit is observed.     

Cellulase applied to the leaves of sweet pepper (Capsicum annuum L. var. grossum) upregulates the production of salicylic and azelaic acids

Treating the leaves of sweet pepper (Capsicum annuum L. var. grossum) with an aqueous solution of cellulase resulted in a four-fold increase in the salicylic acid level compared to a control plant. The level of endogenous azelaic acid was also elevated by the cellulase treatment. Azelaic acid has recently been reported to act as a mobile "priming" agent to arm plants against pathogenic attack. Our results are consistent with this and that the cellulase treatment enhanced the ability of sweet pepper to withstand viral attack.     

辣椒果实性状的遗传分析

以6个辣椒品种并按(1/2)n(n-1)双列杂交法配制的15个杂交组合为材料,根据Hayman分析法估算了辣椒果实5个性状的遗传模型和遗传参数。结果显示,果长、果肉厚和结果数的遗传符合“加性-显性”模型,果宽和单果质量不符合“加性-显性”模型,还存在显著上位性效应。遗传参数估算表明,5个果实性状遗传是以加性效应为主,但不同果实性状显性效应有较大的差异,果肉厚的显性效应最大,其次是果长和结果数,果宽和单果质量最小。     

The Precursors Affecting the Composition of Capsaicin and Its Analogues in the Fruits of Capsicum annuum var. annuum cv. Karayatsubusa

The effects of tropomyosin and troponin on the heat-induced gelation of myosin were investigated by SDS-polyacrylamide gel electrophoresis, scanning electron microscopy and gel rigidity assay, in comparisons with natural and desensitized actomyosin. SDS-polyacrylamide gel electrophoretograms revealed that tropomyosin was almost completely removed from each desensitized actomyosin samples while it was retained in natural actomyosin samples. In spite of this, no significant differences were found in rigidity between natural and desensitized actomyosin gels. No differences could be observed in the microstructure of either actomyosin gel. It may, therefore, be concluded that tropomyosin does not affect the gel texture of the actomyosin system.     

Effects of Seed Number on Competition and Dominance among Fruits in Capsicum annuum L.

The effects of seed number on set, development and growth ofa fruit, and on inhibition of later-developed fruits were studiedby varying the pollen load on the stigma of sweet pepper flowers(Capsicum annuum L.). Despite much variation, a linear increasein individual fruit weight with seed number could be observed.Seed number affected the growth rate rather than the growingperiod of fruit. When seed numbers were low, the probabilityof fruit setting was positively related to seed number. However,a relatively low seed number (50–100 seeds/fruit: 20–30%of the maximum seed number) was sufficient for maximal fruitset. An increase in seed number increased the inhibitory effect ofa fruit on set and growth of later-developing fruits. As a result,when pollination treatments were applied to all the flowersof a plant, results could be quite different to those obtainedwhen only a limited number of flowers were treated. Fruit setof the second fruit was reduced by the application of a highpollen load to the first flower, even when the first fruit abortedbefore it had accumulated much dry matter. Our results suggestthat growth inhibition of the second fruit by seed number ofthe first fruit is controlled both by competition for limitedassimilates, as well as by dominance due to the production ofplant growth regulators by the developing fruit. Sweet pepper; Capsicum annuum L.; pollination; fruit set; abortion; abscission; fruit growth; first-fruit dominance; sink strength     

Growth Analysis of Sweet Pepper (Capsicum annuum L.): 2. Interacting Effects of Irradiance, Temperature and Plant Age in Controlled Conditions

A growth analysis was carried out with sweet pepper plants grownin a phytotron. Irradiance conditions were: 0.84 or 3.25 MJm^–2 in 8 h, 1.67 MJ m^–2 in 16 h and 2.51 MJ m^–2in 24 h. Temperatures applied were 25 or 21 °C during thephotoperiod in combination with 25, 21 and 17 or 21, 17 and13 °C respectively during the nyctoperiod. Highest values for leaf area and total dry weight were foundwhen applying 1.67 MJ m^–2 in 16 h, followed by 3.25 MJm^–2 in 8 h, irrespective of the temperature regime. Continuousirradiance ultimately resulted in leaf drop. A reduction inthe day temperature decreased leaf area and total dry weight.At a day temperature of 25 °C the dry weight increased withdecreasing night temperature when applying 3.25 MJ m^–2in 8 h. At a day temperature of 21 °C leaf area and dryweight were reduced when 17 or 13 °C were applied duringa 16 h nyctoperiod. Values for relative growth rate, net assimilation rate, leafarea ratio and leaf weight ratio strongly decreased with advancingplant age. The effects of irradiance treatment on RGR and NARwere analogous to those on total dry weight while the reversepattern was observed for the LAR. A decrease in day temperaturedecreased the RGR. The effects of night temperature exhibitedstrong interactions with day temperature and photoperiod. Theinfluence of temperature on RGR was largely mediated throughchanges in the LAR. The latter parameter was highly correlatedwith the specific leaf weight. Capsicum annuum L., sweet pepper, growth analysis, irradiance, temperature, plant age     

Development of the male and female gametophyte in Capsicum annuum L. var. California Wonder

The study of reproductive organs and their developmental stages during sporogenesis and gametogenesis is an important step for basic and applied sciences. In this order and to develop knowledge about Capsicum annuum L. (Solanaceae), flower buds in different developmental stages were investigated by light and scanning electron microscopy. The bell pepper bisexual flowers have homoantherous stamens with tetrasporangiate anthers. The pattern of anther wall formation is basic type, while previously described as dicotyledonous type. Microspore mother cells meiosis has simultaneous cytokinesis and tetrads are tetrahedral. Two-celled mature pollen grains are tricolporate with scabrate ornamentation. The gynoecium is bicarpellate and epigynous, with hemianatropous, unitegmic and tenuinucellate ovules. After megaspore mother cell meiosis, cytokinesis is simultaneous. The chalazal megaspore of the linear tetrad functions as the functional megaspore. Embryo sac development is of monosporic Polygonum type and consists of seven cells. We give the first reproductive calendar for the species that allows prognostication of gametogenesis on the basis of sporophytic parameters related to reproductive organ development and floral bud form and size. Some of these developmental characteristics should be useful for comparative studies and investigation of phylogenetic relationships within Solanaceae family.     

甜椒胞质雄性不育雄配子发育的解剖学和超微结构研究

运用石蜡切片和电子显微镜超薄切片方法观察了甜椒(Capsicum annuum L．)细胞质雄性不育系8A和保持系8B雄配子发育过程。结果表明：不育系和保持系都能正常进行减数分裂,绒毡层细胞无明显差异,形成了正常的四分孢子。在四分体单核居中期后,不育系的绒毡层细胞异常膨大并伸进药室,挤压花粉粒,同时绒毡层细胞提前降解,不育系单核晚期花粉粒开始崩出内含物。致使不育系的雄配子在双核花粉粒形成之前就完全裂解,不能发育成正常的花粉粒。此外,超薄切片还观察到不育系花粉粒在单核早期绒毡层细胞线粒体空泡化,这种变化表明雄性不育的遗传缺陷包括在花药发育早期发生的线粒体结构变化。     

Genetic diversity of Chile (Capsicum annuum var. annuum L.) landraces from Northern New mexico, Colorado, and Mexico

Four hundred years of chile(Capsicum annuum var.annuum) cultivation, together with concerns about losing genetic resources in their native agrohabitats, provide the pretext for collecting and preserving landraces of this species in New Mexico. The molecular analysis of these accessions provided a powerful means by which their genetic structures were characterized. Random amplified polymorphic DNA (RAPD) molecular markers were used to compare the relative genetic diversity of native chile landraces to the genetic diversity found in commercially available cultivars in the United States as well as landraces from Mexico.     

Growth Analysis of Sweet Pepper (Capsicum annuum L.): 1. The Influence of Irradiance and Temperature under Glasshouse Conditions in Winter

A growth analysis was carried out with sweet pepper grown ina glasshouse. The plants received natural daylight or additionalillumination applied either during or after the natural photopenod.All irradiance conditions were applied at three temperatureregimes. Additional illumination increased leaf number, leaf area andtotal dry weight. At all temperatures the long-day treatmentsshowed a smaller number of leaves, but a larger leaf area whencompared to the short-day treatments with the same daily radiationsum. A lower temperature progressively reduced leaf area. The derived growth analysis quantities showed strong ontogenetictrends. When comparing both methods of applying additional illuminationhigher mean relative growth rates were observed for the long-daytreatments, especially at the lowest temperature. No differencesin mean net assimilation rate were found, but the short-daytreatments showed a reduced mean leaf area ratio. A lower nighttemperature decreased RGR and NAR but did not affect LAR, alower day temperature increased NAR and decreased LAR. Changesin LAR were largely mediated by changes in specific leaf weight. Capsicum annuum L., sweet pepper, growth analysis, irradiance, temperature     

辣椒花药培养的胚状体分化及其与成苗率的关系

12个辣椒品种的花药培养的结果表明,所有品种均可诱导出胚状体,其中9个品种可获得健壮的再生植株。每一辣椒品种的适宜植物生长调节利配比不同。不同品种的胚状体诱导率和成苗率有差异。成熟的胚状体均能分化成苗,根先分化或停止发育的胚状体很少成苗。