Effect of Low Light on the Characteristics of Photosynthesis and Chlorophyll a Fluorescence During Leaf Development of Sweet Pepper

Low light stress is one of the main limiting factors which influence the production of sweet pepper under protected cultivation in China. In this experiment, two genotypes of sweet pepper, ShY （low light-tolerant genotype） and 20078 （low light-sensitive genotype）, were used to study the effects of low light （photosynthetic photon flux density, PPFD was 75- 100 umol m-2 s-1, control 450-500 umol m-2 s-1） on photosynthesis during leaf development. The result indicated that under low light chlorophyll content, net photosynthetic rate （PN）, photosynthetic apparent quantum efficiency （Фi） and carboxylation efficiency （CE） of sweet pepper leaves increased gradually and decreased after reaching the maximum levels. The time to reach the peak values for all the above parameters was delayed, whereas the light compensation point （LCP） decreased gradually along with leaf expansion. The decrease in maximum quantum yield of PS II （Fv/Fm） was not observed at any stages of the leaf development under low light condition, but the actual PS II efficiency under irradiance （ФPS II） was lower accompanied by an increased non-photochemical quenching （NPQ） in young and/or old leaves compared with mature leaves. The antenna thermal dissipation （D） was a main way of heat dissipation when young leaves received excessive light energy, while the decline in photosynthetic function in senescence leaf was mostly owing to the decrease in carbon assimilation capacity, followed by a significantly increased allocation of excessive energy （Ex）. Compared with 20078, ShY could maintain higher PN, ФPS II and lower QA reduction state for a longer time during leaf development. Thus, in ShY photosynthetic efficiency and the activity of electron transport of PS II were not significantly affected due to low light stress.

Effects of Cyclic Electron Flow Inhibitor(Antimycin A)on Photosystem Photoinhibition of Sweet Pepper Leaves upon Exposure to Chilling Stress Under Low Irradiance

In chloroplast, there were two pathways involved in the cyclic electron flow around photosystem 1 （PS 1）. One was the NADH dehydrogenase （NDH）-dependent flow and the other was the ferredoxin quinone reductase-dependent flow. It was proposed that the NDH-dependent cyclic electron flow around PSI was related to the xanthophyll cycle-dependent non-photochemical quenching （NPQ） at chilling temperature under low irradiance （CL）. The function of the chloroplastic cyclic electron flow around PS 1 was examined by comparing sweet pepper （Capsicum annuum L.） control with its antimycin A （AA）-fed leaves upon exposure to CL stress. During CL stress, the maximum photochemical efficiency of PS2 （Fv/Fm） decreased markedly in both controls and AA-fed leaves, and P700＋ was also lower in AA-fed leaves than in controls. These results implied that cyclic electron flow around PS 1 functioned to protect the photosynthetic apparatus from CL stress. Under such stress, NPQ and PS2-driven electron transport rate were different between AA-fed leaves and controls. The lower NPQ in AA-fed leaves might be related to an inefficient proton gradient across thylakoid membranes （ApH） because of inhibiting cyclic electron flow around PS 1 under CL stress.

Effects of Short-Term Chilling Stress on the Photosystems and Chloroplast Ultrastructure in Sweet Pepper

By measuring chlorophyll fluorescence parameters, composition of fatty acids, active oxygen species and activities ofsome antioxidant enzymes, effects of chilling stress (4C) in the low light (100 mmol m-2 s-1) on chilling-sensitive plants werestudied. After 6 h chilling stress (4C) in the low light, the maximal photochemical efficiency of PSII (Fv/Fm) of sweetpepper leaves decreased by 35.6%, and the oxidizable P700 decreased by 60%. However, chilling stress in the dark had noeffect on both of them. Unsaturation of fatty acids in thylakoid membrane was accelerated, which might be helpful tostabilize photosynthetic apparatus. Distortion and swelling of grana caused by chilling in the dark probably decreasedactivities of antioxidant enzymes, which resulted in the accumulation of active oxygen species. On the contrary,photooxidation might be related to the disintegration and unstacking of grana. Chilling stress induced photoinhibition ofPSII and PSI, and active oxygen species might be one of the factors causing the decrease of the oxidizable P700. PSIseemed to be more sensitive to chilling stress in the low light than PSII.

Indoor Inoculation and Identification Technology of Sweet (Hot) Pepper Virus

[Objective] The paper was to establish an affordable indoor virus inoculation and identification technology. [Method] Taking Tobacco Mosaic Virus （TMV） and Cucumber Mosaic Vires （CMV） of sweet （hot） pepper as the sources of virus, an affordable indoor virus inoculation and identification technology was developed in the paper. [ Result] The suitable inoculation concentration of CMV was five to ten times, and the best seedling age for inoculation was five to six leav- es. Suitable inoculation concentration of TMV was 20 to 30 times, and the best seedling age for inoculation was three to six leaves. Single inoculation technology was mainly used for indoor virus inoculation and identification of sweet （hot） pepper, and complex inoculation technology could also be adopted with first, st inoculation of CMV and late inoculation of TMV. For mixed inoculation technology, CMV： TMV should be 1： 1. Complex inoculation and mix inoculation should base on the tech- nology of single inoculation. Disease resistant materials, AID1-W22-dg176, ABgl-W22-48123, AB91-DL-6428, HY031-2-8-1-6, BYT-4-1-3-6-8, JFG-2-1-2-6, JF8S-1-1-5-4-8 and I＇502-1-1-3-5, were identified by this method. [ Conclusion] This research provided scientific basis for standardization of indoor inoculation of sweet （hot） pepper virus.

Effect of Slow and Controlled Release Fertilizers on the Yield and Nutrient Use Efficiency of Hot Pepper in Qiu-bei

[Objective] The aim of this study was to investigate the impacts of slow and controlled release fertilizers（SCRF）on the yield of qiubei hot pepper,its nutrient use efficiency and environment.[Method] Using Qiubei hot pepper（Capsicum frutescens L.）as the experimental material,we studied the fertilization effect and environment-protecting effect of SCRF.[Result] The result showed that SCRF could improve the agronomic characteristics of hot pepper.Compared to singly applied common fertilizers,SCRF increased economic yield by 20.90% and economic benefit by 13 234.35 Yuan/hm2,and the ratio of output to input was improved by 47.93%.In comparison with common straight fertilizers at same NPK proportion and rate,SCRF increased economic yield by 5.26% and economic benefit by 5 554.80 Yuan/hm2,and the ratio of output to input was improved by 9.91%.Under the reduced use of SCRF by 20%,SCRF increased economic yield by 12.38% and economic benefit by 9595.20 Yuan/hm2 compared with singly applied common fertilizers,and the ratio of output to input was improved by 65.95%.SCRF improved nitrogen,phosphorus and potassium use efficiencies by 12.42-17.53,3.35-5.24 and 5.37-14.02 percents respectively.[Conclusion] As the result of much reduced N and P application rates,SCRF would significantly economize fertilizer resources and minimize the pollution caused by the loss of fertilizer nutrients,which is of practical importance for environment protection.

Relationship between SSR Genetic Distance and Heterosis in Hot Pepper

[Objective] This study aimed to predict the heterosis of hot pepper using SSR genetice distance. [Method] Twenty-five hybridized combinations between 10pepper parents were obtained through NCⅡ incomplete diallel cross to analyze the relationship between SSR genetic distance and heterosis. [Result] The genetic distance of the parents varied in a range from 0.13 to 0.33, and the average genetic distance was 0.25, indicating that the genetic difference was not obvious among the parents, namely, they shared a close genetic relationship. In addition, the SSR genetic distance was closely related to yield per plant and fruits per plant, but showed no obvious correlation with other traits. [Conclusion] This study proved that in a certain range the combinations between the parents with a distant genetic distance possessed stronger heterosis and a larger possibility to produce a high yield and vice versa.

Light Intensity Affects Pungency of Hot Pepper(Capsicum annuum L.) Fruits

This study was carried out both laboratory and field experiment to research the effects of three different light intensity on capsaicin content of hot pepper fruits during the growing stage, the varieties in the study were in different hot levels named No.4 Xiangyan(mid-hot) and No.3 Jingjianjiao(very hot). The study showed that capsaicin content increased accompanied with light intensity weakening. There was an inverse relationship between capsaicin content and peroxidase activity.

RAPD Technique Used to Determine the Purity of Hybrid Hot Pepper Seeds

Two hybrid hot pepper varieties Xiangyan 5 and Xiangyan 10, and their parents were analyzed the polymerase chain reaction with MJ /PT 200 Peltrier Themal Cycler and DS 800 White-ultravilot Transilluminator to set up a RAPD system adaptable to the purity determination of the hy-brid seeds. Among the 39 random primers, 2 and 4 primers were found to be used effectively in Xiangyan 5 and Xiangyan 10 respectively.

Effects of Nitrogenous Fertilizer on Pungency of Hot Pepper (Capsicum annuum L.) Fruits

The response of pungency of hot pepper fruits nitrogenous fertilizer on was invesigated. The results indicated that nitrogenous fertilizer had a significant effect on the capsaicin content of hot pepper fruits at 35 and 42 days after flowering;, capsaicin content gradually decreased, while peroxidase activity increased with nitrogenous fertilizer increasing.

Comparisons of Several Similarity Coefficients for Cluster Analysis of Hot Pepper Germplasm Resources

An appropriate genetic similarity coefficient is particularly important for accurately estimating the genetic similarity and phylogenetic relationship between individuals and evaluating the genetic diversity of populations. In this study, five genetic similarity coefficients were compared for analysis of phylogenetic relationship among 31 hot pepper inbred lines based on SRAP. The applicability of different genetic similarity coefficient was investigated by means of SRAP data of hot pepper inbred lines. According to the experimental results, the variation ranges of Nei ＆ Li, Jaceard, Sorensen, Simple matching and Yule coefficients were 0. 598 - 0. 973, 0. 427 - 0. 947, 0. 598 - 0. 973, 0.427 - 0. 947 and 0. 133 - 0. 997, respectively. Results of cluster analysis based on different similarity coefficients varied greatly. To be specific, clustering results based on Nei ＆ Li, Jaccard and Sorensen coefficients were consistent; clustering with Simple matching and Yule coef ficients led to consistent classification of category in different order and slightly different classification of subcategory. Comprehensively comparing the results of cluster analysis and the dendrograms of hot pepper inbred lines, Yule coefficient is suitable for SRAP analysis of hot pepper.

辣椒的干燥特性和力学性能试验研究

为了降低辣椒在干燥及运输过程中的破损率,提高辣椒的干燥品质,对辣椒进行热风干燥的同时,进行拉伸和三点弯曲力学性能试验研究,并分析了辣椒的干燥特性和力学特性。试验结果表明:当干燥温度为45、60、75℃时,水分有效扩散系数分别为1.160096×10^(-10)、1.713660×10^(-10)、2.380429×10^(-10),随温度升高而升高。由阿伦尼乌斯公式计算得出辣椒活化能为22.0769kJ/mol,表明干燥过程中从辣椒中出去1mol的水分所需的最低能量是22.0769kJ。在75℃干燥温度下的辣椒拉伸力学性能试验中,随着加热时间的增加,平均最大载荷不断增大,加热300min后平均最大载荷曲线开始下降与前面干燥特性吻合,表明辣椒在前300min快速升温,降水速度快,表面自由水失去多,整体韧性增强导致所需载荷增大,干燥后期辣椒含水率较低,脆性增加,拉伸所需最大载荷降低;45℃干燥温度下,随着加热时间的增加,平均最大载荷变化不大。在不同含水率辣椒的三点弯曲试验中,含水率为14%时最大承受载荷约为3.5N,含水率为10%时最大承受载荷为约2.5N,含水率为6%时最大承受载荷约为1.1N,表明随着含水率的减小辣椒所能承受的最大载荷和压缩位移逐渐减小,辣椒抗压能力下降。研究结果可为提高辣椒干燥品质、降低运输过程中的破损提供理论依据。

甜椒新品种‘冀研119’的选育

‘冀研119’是以甜椒雄性不育两用系AB91-WL11-4322为母本,以自交系MY12-2-6-2-3-2为父本选配成的甜椒杂种一代。中早熟,始花节位在9~11节,植株生长势强,连续坐果能力强,果实灯笼形,3~4心室,果面光滑有光泽,商品成熟果为绿色,生理成熟时转黄色,果实纵径10.5 cm左右,果实横径8.9 cm,平均单果鲜质量245 g,果实商品性好,感官品质优良,味甜质脆,可溶性糖含量为32.26 mg/g(FW)、Vc含量108.3 mg/100 g(FW);抗病性强,室内及田间抗病性鉴定结果表明,冀研119耐疫病、抗病毒病、中抗炭疽病。每667 m^(2)平均鲜椒产量4 000 kg,适合在河北石家庄、邯郸、张家口、承德等地采用塑料大棚春提前种植,或在石家庄采用日光温室秋延后种植,在邯郸采用塑料大棚秋延后种植。

遮挡条件下多视角甜椒果实点云三维重构方法

为进行表型原位自动化测量,实现甜椒数字化育种和管理,针对原位果实表型测量中的目标遮挡问题,提出一种多视角甜椒果实点云的三维重构方法。通过虚拟叶片的方法,创建增强数据集,建立基于YOLO v5算法的甜椒果实识别模型,实现对不同遮挡程度果实的识别,同时,构建考虑果实位置与遮挡程度的果实表型采集算法,实现多视角的果实三维数据采集。最后,配准甜椒果实三维点云,提取甜椒表型参数,并通过温室甜椒果实表型,对点云重构方法的有效性进行验证。相较手动测量数据,果实果宽平均相对误差为1.72%,果高平均相对误差为1.60%。试验结果表明,本文所提出的甜椒原位表型点云重构方法,可为遮挡条件下作物表型提供有效的解决思路和可行方法。

中卫市退砂土地农作物复垦的可行性分析研究

本研究旨在分析宁夏中卫市沙坡头区退砂地的土壤质量提升及农作物种植适宜性。通过连续3年的田间试验,收集并分析了8种宁夏地区广泛栽培的耐旱作物对土壤理化性质的影响及其经济效益。分析了退砂耕地适生农作物对当地土壤质量的影响及经济效益。结果表明,朝天椒和红葱在退砂地上表现出较高的产量和产值,且投入产出比大,是退砂地优先选择的作物。此外,玉米和小杂粮等作物轮作种植也显示出改良土壤结构和提高肥力的潜力。本研究为退砂地的科学利用提供了理论依据和实践指导,有助于推动中卫市经济社会可持续发展。

辣椒新品种辣研509的选育

辣研509是以雄性不育系y92-1A作母本、自交系GJH-4-2①作父本组配选育而成的三系杂交鲜食型线椒新品种。始花节位8节左右,中早熟,果实线形、单生向下,全生育期约179 d。青果绿色、老熟果红色,果面光亮微皱。果实纵径20.36 cm、横径1.83 cm,果肉厚度0.148 cm,单果鲜质量14.58 g;果实维生素C含量(w,后同)173 mg·100 g^(-1),辣椒素含量0.15%。抗病毒病、炭疽病,中抗疫病。667 m^(2)鲜椒产量1547.65 kg,产量稳定,丰产。适宜在贵州、宁夏、新疆等地进行保护地及露地种植。2022年12月通过农业农村部非主要农作物品种登记。

气候条件对黔北地区辣椒产量的影响与气象产量预测模型研究

【目的】探明影响黔北地区辣椒产量的关键气象因子、关键时段以及气象条件对黔北地区辣椒产量的影响强度,为黔北地区辣椒生产决策、气候影响评估和产量预测提供理论依据。【方法】采用产量分离方法和数理统计对影响黔北地区辣椒产量的关键气象因子、关键时段以及关系进行研究;并以播州区为研究区,研究辣椒气象产量预测模型。【结果】6月的平均气温和最高气温越高,越不利辣椒产量形成;8月下旬至9月中旬的最低气温为产量的限制性因子,最低气温越高则产量越高。在日较差大于8.5℃的情况下,随着日较差的增大,辣椒产量呈缓慢增加趋势。6月下旬的降水量为辣椒生长的水分限制因子,降水量增多则产量增高。4月中旬至5月上旬、6月中旬至下旬的日照时数与气象产量呈负相关。播州区辣椒气象产量预测模型为Y_(w)=-40.836T_(6月中旬至下旬)+40.644T_(8月上旬)-106.159。【结论】黔北地区气象条件对辣椒产量影响程度达±50%左右。不同区域气象条件对辣椒产量影响的关键时段不同,播州区气候条件影响的关键时段在中后期。辣椒生长中期,温度与辣椒产量呈显著负相关;除播州区6月下旬降水量限制辣椒生长外,大部分县市区降水均能满足辣椒生长需要;日照时数对辣椒产量的影响呈前期为正,后期为负。

基于不同包装材料和杀菌方式的糟辣椒贮藏品质变化及货架期预测

目的研究不同包装材料和杀菌方式对糟辣椒贮藏品质的影响,并对糟辣椒的货架期进行预测。方法以花溪新鲜红辣椒制作的糟辣椒为研究对象,探索高温蒸煮袋、铝箔袋、聚丙烯(polypropylene plastic,PP)塑料瓶、聚对苯二甲酸乙二醇酯(polythylene terephthalate,PET)塑料瓶、玻璃瓶5种包装材料和巴氏杀菌、蒸汽灭菌、微波杀菌、超高压杀菌、辐照杀菌5种杀菌方式对糟辣椒贮藏品质的影响,通过加速货架期测试法(accelerated shelf life testing,ASLT)和Q10货架期预测模型对糟辣椒的货架期进行预测。结果糟辣椒袋装材料以铝箔袋包装效果较好,瓶装以玻璃瓶包装效果较好;糟辣椒经5种杀菌方式处理后,硬度和咀嚼性略有减小,菌落总数显著降低。随着贮藏时间的延长,不同杀菌处理可降低糟辣椒亚硝酸盐峰值,保持色泽,维持质地特性,延缓微生物的生长。整体上,冷杀菌效果优于热杀菌,但超高压杀菌对糟辣椒感官品质有影响(产生异味),因此,辐照杀菌较适合用于糟辣椒的杀菌。通过ASLT法和Q10货架期预测模型得到优化后糟辣椒在25℃的货架期约为219 d。结论玻璃瓶包装的糟辣椒经辐照冷杀菌处理,与未杀菌的玻璃瓶包装糟辣椒相比,货架期延长了121 d,该研究可为提升糟辣椒贮藏品质提供参考。

枯草芽孢杆菌B2-GFP菌株对甜椒幼苗生长和生理特性的影响

【目的】筛选能促进甜椒幼苗生长的枯草芽孢杆菌B2-1GFP菌株发酵液适宜浓度,为研发菌肥作用于蔬菜提供依据。【方法】以甜椒硕源808为材料,设置枯草芽孢杆菌B2-1GFP菌株发酵液T1(1×105 CFU·mL^(-1)1)、T2(1×10^(6)CFU·mL^(-1)1)、T3(1×10^(7)CFU·mL^(-1)1)、T4(1×10~8 CFU·mL^(-1)1)4个浓度梯度处理,每隔7 d向植株浇灌菌株发酵液,连续浇灌3次,每次每株浇灌5 mL,21 d时测定甜椒幼苗生长指标、生物量积累、叶片光合特性、叶绿素荧光参数、根系抗氧化酶活性、根系形态建成及根系活力指标。【结果】与对照相比,不同浓度枯草芽孢杆菌B2-1GFP菌株发酵液可提高甜椒株高、叶面积、叶绿素含量、植株生物量,以1×10^(6)CFU·mL^(-1)1的增幅最大。同时,该浓度显著提高了叶片蒸腾速率(Tr)、气孔导度(Gs)、最大荧光(Fm)、PSⅡ实际光化学效率(ФPSⅡ)和光化学荧光猝灭系数(qP),降低了胞间CO_(2)浓度(Ci)和叶绿素基础荧光(F_o);提高甜椒根系过氧化物酶(POD)、过氧化氢酶(CAT)、超氧化物歧化酶(SOD)、苯丙氨酸解氨酶(PAL)、多酚氧化酶(PPO)活性及根系活力。【结论】在甜椒移栽后浇灌1×10^(6)CFU·mL^(-1)1B2-1GFP菌株发酵液可促进甜椒植株生长和根系形态建成,增强叶片光合能力,提高生物量积累、根系抗氧化酶活性和根系活力。

热风干燥甘薯片的热质传递分析

为探究甘薯片在热风干燥过程中的温度和水分分布,建立数值模型来模拟不同恒定干燥温度(50,60,70,80℃)的传热、传质过程。由于物料在热风干燥过程中会发生较为明显的收缩效应,其有效水分扩散系数会发生改变,对模拟的精准度产生影响,因此对比了依赖温度、收缩相关扩散系数两种方式的传热、传质过程。结果表明,基于收缩相关的有效水分扩散系数能准确地描述甘薯片的热风干燥过程,其中依赖收缩的水分比以及温度的模拟值与试验值的决定系数(R~2)在0.976~0.994和0.961~0.981之间。为了分析不同热风温度对甘薯片干燥后质量的影响,从色差、复水率及感官评分方面分析,得出60℃为甘薯片热风干燥的最佳温度。模拟试验结果表明,有效水分扩散系数随热风温度的升高而上升,传热、传质系数对甘薯片温度变化以及干燥过程的影响十分显著。所开发的模型可为不同干燥温度下模拟研究其它农作物的干燥过程提供借鉴。