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.

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 Pehrier 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。

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。

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。

基于顶空固相微萃取-气相色谱-质谱的糟辣椒挥发性物质非靶标代谢组学分析

为了探究不同品种辣椒制作的糟辣椒风味特征差异,选取在贵州地区广泛种植的4个辣椒品种成熟果实制作成糟辣椒,采用顶空固相微萃取-气相色谱-质谱法检测分析其挥发性物质。结果表明:黄平线椒(HP)、林卡辣椒(LK)、黔椒8号(Q4)和辣研101(LY)分别含有60、71、55种和65种挥发性物质,其中HP、LK和Q4含量最高的挥发性物质是乙酸,LY含量最高的挥发性物质是香叶醇,4种糟辣椒含有24种共有物质。通过相关性分析发现,糟辣椒中醇类与烷烃类、烯烃类物质,酯类与酮类物质均呈显著负相关(P<0.05),烯烃类和烷烃类物质呈显著正相关(P<0.05);正交偏最小二乘判别分析表明,4种糟辣椒组间的差异挥发性物质种类均在10种以上,其中HP vs Q4和LK vs Q4最主要的差异物质为乙酸-2-苯乙酯,LY vs Q4和LK vs LY最主要的差异物质为乙酸、LK vs HP最主要的差异物质为苯代丙腈。基于糟辣椒9类挥发性物质建立综合品质评价模型,最终得出4种糟辣椒挥发性风味品质由高到低的顺序:HP>LY>LK>Q4。本研究对了解不同品种辣椒制作的糟辣椒挥发性风味差异具有一定意义,可为糟辣椒的原料选择等提供一定参考依据。

甜椒幼苗低温胁迫的生理响应与转录组分析

为了阐明甜椒响应低温胁迫的分子机制,对低温胁迫时甜椒幼苗的MDA含量、SOD活性以及光合作用相关参数进行了测定,并结合转录组测序分析。结果表明:低温胁迫3 d时甜椒MDA含量显著升高,SOD活性显著降低,光合相关参数显著下降;与低温处理前相比,转录组测序分析结果显示检测出差异基因主要涉及酶系统、光合作用、信号传导以及相关转录因子,其中SOD相关基因CaSOD呈示上调表达,光合作用关键基因CaCP4与CaHCR的表达量则显著下调。研究结果为深入解析甜椒幼苗响应低温胁迫的分子机制及甜椒抗低温育种奠定了基础。

膨润土对沙地土壤改良与朝天椒农艺性状及产量的影响

探索膨润土对沙地土壤性质及结构、朝天椒农艺性状及产量的影响,为膨润土用于沙地土壤改良应用提供理论依据。于2023年在内蒙古自治区鄂尔多斯市杭锦旗巴拉贡镇山湾村开展膨润土治理沙化耕地大田试验,试验按膨润土施量共设置6组处理,分别为:0(CK)、15.0 t/hm^(2)(A1)、22.5 t/hm^(2)(A2)、30.0 t/hm^(2)(A3)、37.5 t/hm^(2)(A4)、45.0 t/hm^(2)(A5),研究不同膨润土施量对土壤理化性质及结构和朝天椒农艺性状及产量的影响。结果表明:与对照相比,施用膨润土能够显著改善土壤性质、有效调整土壤结构。膨润土的施用提高了朝天椒生育期内土壤含水量、总孔隙度、CO_(2)通量、WR>0.25 mm含量、pH和电导率;降低了生育期内土壤容重,协调了生育期内土壤三相比例,改善土壤固液气结构。在生育期内膨润土施量与土壤总孔隙度呈极显著正相关,与土壤容重呈极显著负相关。施用膨润土有效促进了朝天椒的生长发育,显著提高朝天椒产量。以A3处理朝天椒产量最高,较对照增产61.2%。膨润土作为土壤改良剂能够有效改善土壤性质,调整土壤结构,提高土壤持水能力和朝天椒产量。综合不同施量对土壤指标及朝天椒产量的影响,研究认为30.0 t/hm^(2)为该试验区2023年适宜施量。

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。

辣椒新品种皇鼎一号的选育

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