Effects of Chlorine Dioxide Gas on Postharvest Physiology and Storage Quality of Green Bell Pepper (Capsicum frutescens L.var.Longrum)

The effects of treatment of chlorine dioxide （C1Oz） gas on postharvest physiology and preservation quality of green bell peppers were studied. Green bell peppers were collected in bags and treated with 0, 5, 10, 20, and 50 mg L^-1 ClO2 gas at 10±0.5℃ for over 40 d, and the changes in postharvest physiology and preservation quality of the peppers were evaluated during the storage. The inhibition of rot of the peppers was observed for all the tested ClO2 gas treatments. The rot rates of the treated samples were 50% lesser than those of the control after day 40 of storage. The highest inhibitory effect was obtained after 50 mg L^-1 ClO2 gas treatment, where the peppers did not decay until day 30 and showed only one-fourth of the rot rate of the control at day 40 of storage. The respiratory activity of the peppers was significantly （P〈0.05） inhibited by 20 and 50 mg L^-1 ClO2 treatments, whereas no significant effects on respiratory activity were observed with 5 and 10 mg L^-1 ClO2 treatments （P〉0.05）. Except for 50 mg L^-1 ClO2, malondialdenyde （MDA） contents in the peppers treated with 5, 10, or 20 mg L^-1 ClO2 were not significantly （P〉0.05） different from those in the control. Degradation of chlorophyll in the peppers was delayed by 5 mg L-1ClO2, but promoted by 10, 20, or 50 mg L^-1 ClO2. The vitamin C content, titratable acidity, and total soluble solids of the peppers treated by all the tested ClO2 gas did not significantly change during the storage. The results suggested that ClO2 gas treatment effectively delayed the postharvest physiological transformation of green peppers, inhibited decay and respiration, maintained some nutritional and sensory quality, and retarded MDA accumulation.

甜椒(Capsicum frutescens L.)离体再生体系的构建

为建立一个稳定、高效的甜椒离体再生体系,本试验以2种基因型的甜椒(野生型CA157和栽培型CA52)为材料,筛选其最佳外植体类型,优化激素配比及浓度来提高愈伤组织的诱导率和子叶节的分化率。通过筛选以野生甜椒CA157、栽培甜椒CA52的子叶节为外植体,结果表明,野生甜椒CA157子叶节愈伤组织诱导率和分化率分别达到82%和73%。栽培甜椒CA52子叶节最高愈伤组织诱导率和分化率分别为81%和70%。诱导愈伤组织最适培养基是MS+2 mg/L TDZ+0.5 mg/L 2,4-D。诱导不定芽形成的最适培养基为MS+2 mg/L TDZ+1.5 mg/L 6-BA,诱导不定芽成活率最高。在不定芽诱导生根培养基(1/2MS+20 g/L蔗糖+1.5 mg/L ABT)上,生根率为67%,每个不定芽生根数最高达到4.2,移栽后再生植株成活率达73%。2个甜椒品种都能得到再生植株而且繁殖系数高。本培养体系适宜甜椒离体再生。通过染色体分析,再生植株染色体数和供体亲本材料一致,初步表明再生植株遗传稳定。

生物降解地膜对辣椒生长发育的影响

为明确不同材质生物可降解地膜对辣椒(Capsicum frutescens)生长发育的影响,选用聚乙烯地膜(PE)、天然产物类(PM1、PM2)、合成聚合物类降解膜[聚己二酸/对苯二甲酸丁二酯(PBAT)、聚羟基脂肪酸酯(PHA)等](PM3、PM4、PM5)进行田间试验,观察不同地膜的增温作用、降解性能和不同地膜覆盖下辣椒的生长性状。结果表明,辣椒生育前期(覆膜后0~52 d)是地膜增温的主要时期,覆膜种植主要提高该时期0~5 cm和5~10 cm土层各时间段土壤温度。其中,PM5的增温效果与PE相近,5~10 cm和10~15 cm土层土壤平均温度比CK(露地种植)提高了2℃以上。地膜覆盖使辣椒株高在覆膜后24~47 d得到明显生长,平均增长了20.28 cm,在覆膜后39 d,PM5比CK提高了8.2 cm;不同覆膜处理的辣椒叶绿素SPAD在覆膜后23 d存在显著差异,PM5和PE显著高于CK,分别提高了5.67和3.70。地膜覆盖对辣椒产量的影响表现为PM3、PM4、PM5处理的辣椒总产量均显著高于CK,分别提高了4 123、4 445、5 552 kg/hm^(2),其增产效果接近或优于PE,其中PM5对辣椒产量提升的效果最明显。因此,辣椒露天栽培推荐使用厚度为0.01 mm,主要成分为PBAT、PHA的可降解地膜。

Phenotypic Variation among and within Three Peppers Species(Capsicum)from Mexico

The phenotypic variation and its distribution among species,morphotypes,and among and within populations was estimated in 71 populations pertaining to 15 morphotypes of three domesticated species of Capsicum from Mexico.Collections were made in the states of Sinaloa,Nayarit,Oaxaca,Tabasco,and Yucatán in two agroecosystems:Backyard-garden and monoculture.Fifteen phenotypic characteristics were analyzed through one-way variance analysis and multivariate analyses of principal components analysis(PCA)and hierarchical clustering using Ward’s method.The study was performed in a uniform greenhouse experiment.A high variation was found among and within populations in all the measured characteristics.Of the total variation,13.0%was distributed among species,27.9%among morphotypes,8.1%among populations,and 51.0%within populations.Because plants grew in a uniform environment,these results indicate that the differences observed among and within species,morphotypes,and populations have a genetic basis.Univariate and multivariate analyses clearly differentiated morphotypes,suggesting that the category of morphotypes must be used to nominate the infraspecific variation in the domesticated Capsicum.The principal components analysis identified a total of 15 principal components that contributed to explain the total variation.The first two components explained 59.64%of the total variation and seven components explained more than 90%of the total variation.Among the measured characteristics,number of seed per fruit,weight of the fruit,width of the fruit,length of the fruit,stem diameter,days to flowering,and height of the plant contributed to component 1 variation,whereas width of the leaf,length of the leaf,and number of locules,number of fruits and number of seeds per plant contributed to component 2.The hierarchical clustering separated the populations and the morphotypes in two large different groups.One group consisted of populations collected in monoculture conditions and the other group corresponded to population collected from backyard-garden conditions.The monoculture populations were characterized mainly by their longer,wider,and higher weight fruits,plants were of less height,had smaller stem diameters,and lower number of fruits than the populations collected from the backyard-garden conditions.The backyard-garden populations of the Capsicum annuum and Capsicum frutescens species,considered wild or semi-domesticated,constituted a non-differentiated phenotypic group that does not allow dividing them in different species.

膜下滴灌条件下水氮耦合对辣椒根系生长及产量的影响

为探究膜下滴灌条件下水氮耦合对辣椒(Capsicum frutescens L.)根系及产量的影响,采用大田小区试验,在辣椒开花坐果期和盛果期进行轻度亏缺(W1,3656 m^(3)/hm^(2))和中度亏缺(W2,3082 m^(3)/hm^(2))的调亏灌溉,并设置纯氮施用量325 kg/hm^(2)(N1,高氮)、250 kg/hm^(2)(N2,中氮)、175 kg/hm^(2)(N3,低氮)3个施氮水平,以传统模式(灌水量4230 m^(3)/hm^(2),施氮量325 kg/hm2)为对照(CKN1),研究了不同灌水量和施氮量组合对辣椒根系生长和产量、灌溉水利用效率、氮肥偏生产力的影响。结果表明,灌水量、施氮量及二者的耦合效应对辣椒产量和根系生长、灌溉水利用效率、氮肥偏生产力有显著影响(P<0.05)。W1N2处理辣椒产量最高,为35189 kg/hm^(2),与其他处理相比,增产了4.37%~55.73%,且W1N2处理灌溉水利用效率最高,氮肥偏生产力也较高。辣椒根系生长以CKN1处理最佳,W1N2处理次之,二者无显著差异。灌水量和施氮量与辣椒根系分布参数不存在正相关性,但二者耦合效应越明显,辣椒根系生长越发达。综合得出,灌水量3656 m^(3)/hm^(2)、施氮量250 kg/hm2为北疆地区辣椒种植最佳水氮组合。

^(60)Co-γ辐射对朝天椒种子诱变效应的影响

为探究辐射处理对朝天椒种子诱变效应的影响,确定辐射诱变朝天椒种子的最适宜条件。本研究选用朝天椒常规种‘中农千斤红’为试材,以25、50、100、200、300、400、500和600 Gy为辐射剂量处理,以不辐照(0 Gy)干种子为空白对照,分别对诱变种子发芽情况进行分析;60 d观测成苗植株形态状况和叶片气孔器特征;测定成苗叶片主要生理指标。结果表明,种子发芽力(发芽势,发芽率)、发芽指数、出苗率、成苗率和壮苗率随着辐射剂量的增加而降低,致畸率则上升;随着辐射剂量的增加,植株表型性状突变情况愈加明显;超氧化物歧化酶(SOD)活性、过氧化物酶(POD)活性、过氧化氢酶(CAT)活性和可溶性糖含量先上升后下降,在辐射剂量为400 Gy时出现最大值;叶绿素a、叶绿素b、类胡萝卜素含量一直呈现下降趋势,丙二醛(MDA)含量和相对电导度持续升高;叶片上、下表皮的气孔密度逐渐增加,保卫细胞长先增大后减小,保卫细胞宽和气孔开度先减小后增大。在^(60)Co-γ辐射为100 Gy时发现优良变异株,结合回归分析,最终确定该品种辐射剂量的半致死剂量为377.14 Gy,也为最适诱变剂量。通过朝天椒材料诱变以期获得一些可遗传的变异,能为诱变育种提供依据和参考。

Screening for larvicidal activity of ethanolic and aqueous extracts of selected plants against Aedes aegypti and Aedes albopictus larvae

Objective:To screen for larvicidal activity of aqueous and ethanolic extracts(95%ethanol)from Selaginella elmeri,Christella dentata,Elatostema sinnatum,Curculigo capitulata,Euphorbia hirta,Murraya koenigii(M.koenigii),Alpinia speciosa,Cymbopogon citratus,Eucalyptus globulus(E.globulus),Jatropha curcas(J.curcas),Psidium guajava,Gliricidia sepium,Ixora coccinea and Capsicum frutescens(C.frutescens)against Aedes aegypti(A.aegypti)and Aedes albopictus(A.albopictus)3rd instar larvae.Methods:Ethanolic and aqueous extracts were screened for larvicidal activity by exposing the A.aegypti and A.albopictus 3rd instar larvae(15 larvae per trial,triplicates)for 48 h,counting the mortalities every 24 h.Additionally,phytochemical screening for flavonoids,tannins,alkaloids,anthraquinones,anthrones,coumarins,indoles and steroids were performed on active extracts using spray tests.Results:Against A.aegypti,the three most active extracts were C.frutescens ethanolic(100%after 24 and 48 h),J.curcas ethanolic(84.44%after 24 h and 88.89%after 48 h)and M.koenigii ethanolic(53.33%after 24 h and 71.11%after 48 h).On the other hand,against A.albopictus,the three most active extracts were C.frutescens ethanolic(93.33%after 24 h and 100%after 48 h),J.curcas ethanolic(77.78%after 24 h and 82.22%after 48 h)and E.globulus ethanolic(64.44%after 24 h and 73.33%after 48 h).Phytochemical screening was also performed on the active extracts,revealing alkaloids,tannins,indoles and steroids.Conclusios:The results demonstrate the larvicidal activities of ethanolic extracts of Cymbopogon citratus,Euphorbia hirta,Ixora coccinea,Gliricidia sepium,M.koenigii,E.globulus,J.curcas and C.frutescens against A.aegypti and A.albopictus 3rd instar larvae.These could be used as potential larvicidal agents for the control of these mosquitoes.