为研究冬春反季节设施栽培辣椒果实绿熟到转色阶段的品质及形态指标在发育过程中的变化规律，以4个辣椒品种和2个甜椒品种为研究对象，对授粉后果实不同生长发育阶段辣椒果实单果重、果长、果肩宽等形态指标及可溶性糖含量和维生素C等品质指标进行检测分析。结果表明，辣椒授粉后7~27 d为辣椒果实快速增长期，辣椒果实开花后37~42 d为最佳采收期，此时水分含量较高，维生素C、可溶性糖和可溶性固形物含量及单果重基本都达到了整个生长发育阶段的峰值。相关性分析表明，果实形态指标与单果重均呈显著正相关关系；维生素C含量、果实可溶性固形物含量、可溶性总糖含量与单果重及大部分果实形态指标均呈显著正相关关系，但与果实含水量均呈极显著负相关关系；可溶性固形物含量与维生素C含量、可溶性糖含量均呈极显著正相关关系。

比较低温处理下不同砧木表型差异、嫁接方法和嫁接叶龄对嫁接成活率的影响，为筛选辣椒耐低温砧木和优化辣椒嫁接体系提供依据。结果发现，野生茄子S2的耐低温能力较强，可以作为辣椒嫁接耐低温砧木；在砧木二叶一心和接穗三叶一心时，采用劈接法嫁接成活率最高。研究结果为提高春提早和秋延后设施栽培辣椒植株的耐低温能力提供了实践依据。

为了探讨EBR(2,4-表油菜素内酯)对金线莲耐高温胁迫的影响,本文研究了高温胁迫下喷施EBR对金线莲叶片中活性氧代谢的影响。结果表明,高温胁迫导致金线莲大量积累ROS,使细胞受到伤害,其O₂^-产生速率和H₂O₂含量显著增加,AsA含量显著下降,SOD、CAT、APX、MDHAR、DHAR、GR等酶活性显著下降;而外源喷施1.0 μmol·L^-1 EBR可显著提高SOD、CAT、MDHAR、DHAR和GR的活性,AsA含量上升,O₂^-产生速率和H₂O₂含量显著下降。由此可见,外源EBR处理可以提高金线莲叶片抗氧化酶活性,有效清除活性氧,增强植株抵抗高温胁迫的能力,本研究结果为生产上喷施EBR缓解金线莲高温胁迫提供了理论依据。

Ralstonia solanacearum causes bacterial wilt disease, leading to severe crop losses. Xylem sap from R. solanacearum-infected tomato is enriched in the disaccharide trehalose. Water-stressed plants also accumulate trehalose, which increases drought tolerance via abscisic acid (ABA) signaling. Because R. solanacearum-infected plants suffer reduced water flow, we hypothesized that bacterial wilt physiologically mimics drought stress, which trehalose could mitigate. We found that R. solanacearum-infected plants differentially expressed drought-associated genes, including those involved in ABA and trehalose metabolism, and had more ABA in xylem sap. Consistent with this, treating tomato roots with ABA reduced both stomatal conductance and stem colonization by R. solanacearum. Treating roots with trehalose increased xylem sap ABA and reduced plant water use by lowering stomatal conductance and temporarily improving water use efficiency. Trehalose treatment also upregulated expression of salicylic acid (SA)-dependent tomato defense genes; increased xylem sap levels of SA and other antimicrobial compounds; and increased bacterial wilt resistance of SA-insensitive NahG tomato plants. Additionally, trehalose treatment increased xylem concentrations of jasmonic acid and related oxylipins. Finally, trehalose-treated plants were substantially more resistant to bacterial wilt disease. Together, these data show that exogenous trehalose reduced both water stress and bacterial wilt disease and triggered systemic disease resistance, possibly through a Damage Associated Molecular Pattern (DAMP) response pathway. This suite of responses revealed unexpected linkages between plant responses to biotic and abiotic stress and suggested that R. solanacearum-infected plants increase trehalose to improve water use efficiency and increase wilt disease resistance. The pathogen may degrade trehalose to counter these efforts. Together, these results suggest that treating tomatoes with exogenous trehalose could be a practical strategy for bacterial wilt management.

The present study evaluated the priming efficacy of chitosan and chitosan-derived nanoparticles (CNPs) against bacterial wilt of tomato. In the current study, seed-treated CNPs plus pathogen-inoculated tomato seedlings recorded significant protection of 62 % against pathogen-induced wilt disease and subsequently better growth. The induced resistance was witnessed by a prominent increase in lignin, callose and HO deposition, followed by superoxide radical accumulation in leaves. Additionally, chitosan and CNPs-treated tomato plants recorded a remarkable increase in the upregulation of phenylalanine ammonia-lyase (PAL), peroxidase (POX), polyphenol oxidase (PPO), catalase (CAT) and β-1, 3 glucanase (GLU) in comparison with untreated plants. The chitosan and CNPs-induced antioxidant enzymes were positively correlated with the stimulation of corresponding gene expression in CNPs treated plants related to pathogen-inoculated ones. The results of this study describe that how the application of chitosan and CNPs elicit defense responses at the cellular, biochemical and gene expression in tomato plants against bacterial wilt disease, thereby improve growth and yield.Copyright © 2022 Elsevier B.V. All rights reserved.

为明确黄瓜对尖孢镰孢菌的抗性机理，选择黄瓜抗病和感病材料进行尖孢镰孢菌接种，以接种灭菌水为对照，分析接种后抗病和感病材料的生物学性状及叶片游离氨基酸的动态变化规律差异。结果显示:①接种后20 d，抗病材料的株高、茎粗、叶面积、总根长、根总面积、根总体积、根冠比、壮苗指数与对照差异不显著；而在感病材料中表现为染菌处理显著低于对照，其中总根长表现最为明显,较对照减少51.02%。②接种病原菌后，抗病材料游离氨基酸呈下降趋势，感病材料游离氨基酸呈上升趋势。接种病原菌后8、12、16、20 d，抗病材料游离氨基酸总量几乎不受病原菌的影响，感病材料的游离氨基酸总量分别较对照增加14.05%、32.54%、56.29%、149.10%。③在测定的34种游离氨基酸中，有16种在抗病和感病材料中的变化规律明显不同。瓜氨酸和丙氨酸在抗病材料中表现为染菌处理小于对照或与对照差异不显著，而在感病材料中表现为染菌处理大于对照；酪氨酸、牛磺酸、蛋氨酸、亮氨酸、β氨基异丁酸、鸟氨酸、赖氨酸和脯氨酸的表现则相反。接种后随着幼苗生长，瓜氨酸、天冬酰胺、磷酸丝氨酸、尿素、β丙氨酸、组氨酸、鸟氨酸和精氨酸含量在抗病材料中呈下降趋势，而在感病材料中呈上升趋势。推测瓜氨酸、丙氨酸、天冬酰胺、磷酸丝氨酸、尿素、β丙氨酸、组氨酸和精氨酸为促菌氨基酸，酪氨酸、牛磺酸、蛋氨酸、亮氨酸、β氨基异丁酸、赖氨酸和脯氨酸为抑菌氨基酸。上述结果为黄瓜抗枯萎病育种提供参考依据和理论背景。

EG03菌剂由多种抗青枯劳尔氏菌(Ralstonia solanacearum)的拮抗细菌复配而成，田间施用能有效防治辣椒青枯病，平均防效达85.8%.采用稀释平板法、最大或然数(MPN)法以及Biolog微孔板培养系统研究了EG03菌剂对田间辣椒根围土壤微生物群落特征的影响.结果表明： EG03菌剂对根围土壤微生物群落的影响随时间变化而不同，施用后不同程度提高了真菌和芽孢杆菌的数量，并显著增加了自生固氮细菌的数量.根围土壤微生物群落平板每孔颜色平均变化率（AWCD）的变化随培养时间呈现典型的“S”型曲线，辣椒生长后期根围土壤AWCD值高于前期.6类碳源利用分析表明，EG03菌剂的施用在短期内会降低根围土壤微生物的碳源利用率，辣椒生长后期根围土壤中以糖类物质作为碳源的微生物占主导地位.微生物多样性指数分析发现，EG03菌剂施用前期会不同程度降低根围土壤微生物各项多样性指数，但施用后期会提高各项多样性指数，尤其在Simpson指数和McIntosh均匀度两项指标上差异显著.

Xyloglucan, the primary hemicellulosic cell wall polysaccharide in dicotyledons, undergoes substantial modification during auxin-stimulated cell expansion. To identify candidates for mediating xyloglucan turnover, the expression and auxin regulation of tomato Cel7 and LeEXT, genes encoding an endo-1,4-beta-glucanase (EGase) and a xyloglucan endotransglycosylase (XET), respectively, were examined. LeEXT mRNA was present primarily in elongating regions of the hypocotyl and was induced to higher levels by hormone treatments that elicited elongation of hypocotyl segments. Cel7 mRNA abundance was very low in both elongating and mature regions of the hypocotyl but was induced to accumulate to high levels in both hypocotyl regions by auxin application. Analysis of the time dependence of expression of Cel7 and LeEXT during auxin treatment suggested that induction of these genes is not required for rapid growth responses but may participate in the cell wall changes involved in sustained cell elongation. Localization of Cel7 and LeEXT mRNA by in situ hybridization revealed that both genes are expressed in outer cell layers of the hypocotyl. In untreated etiolated seedlings, LeEXT mRNA was detected in epidermal cells of the elongating region, a tissue considered to play a key role in auxin-induced elongation. After auxin treatment, Cel7 and LeEXT mRNA showed an overlapping spatial distribution in the epidermis and outer cortical cell layers. We conclude that LeEXT and Cel7 exhibit both unique and overlapping patterns of expression and have the potential to act cooperatively in mediating cell wall disassembly associated with expansive growth.

Walls isolated from cucumber hypocotyls retain autolytic activities and the ability to extend when placed under the appropriate conditions. To test whether autolysis and extension are related, we treated the walls in various ways to enhance or inhibit long-term wall extension ('creep') and measured autolysis as release of various saccharides from the wall. Except for some non-specific inhibitors of enzymatic activity, we found no correlation between wall extension and wall autolysis. Most notably, autolysis and extension differed strongly in their pH dependence. We also found that exogenous cellulases and pectinases enhanced extension in native walls, but when applied to walls previously inactivated with heat or protease these enzymes caused breakage without sustained extension. In contrast, pretreatment of walls with pectinase or cellulase, followed by boiling in methanol to inactivate the enzymes, resulted in walls with much stronger expansin-mediated extension responses. Crude protein preparations from the digestive tracts of snails enhanced extension of both native and inactivated walls, and these preparations contained expansin-like proteins (assessed by Western blotting). Our results indicate that the extension of isolated cucumber walls does not depend directly on the activity of endogenous wall-bound autolytic enzymes. The results with exogenous enzymes suggest that the hydrolysis of matrix polysaccharides may not induce wall creep by itself, but may act synergistically with expansins to enhance wall extension.

本文总结了我国植物细菌性病害的类别及发病特点、植物病原细菌的侵入和传播途径,并从化学防治、生物防治、农业防治、物理防治和抗病品种选育等方面概述了现阶段我国植物细菌性病害的防治措施,最后提出植物细菌性病害的绿色防控措施,为有害生物绿色防控和植物健康可持续发展提供参考。

为了减少设施番茄生产中农药化肥的使用,集成了土壤熏蒸及水肥菌/药一体化技术,并在湖北十堰开展了设施番茄病害的综合防控试验示范。试验设置3个处理,分别为CK(不做土壤熏蒸+水肥药常规化管理)、T1(土壤熏蒸+水肥药常规化管理)、T2(土壤熏蒸+水肥药一体化管理)。田间试验结果表明:采用土壤熏蒸可使番茄的根结线虫病降低70.7%~75.0%,灰霉病、早疫病和青枯病的综合发病率降低33.0%~63.7%,产量增加25.0%左右;土壤熏蒸结合水肥菌/药一体化技术可使番茄的根结线虫病降低 82.7%~85.1%,灰霉病、早疫病和青枯病的综合发病率降低70.2%~74.0%,产量增加35.9%~41.0%。相对于常规管理措施,采用水肥菌/药一体化技术可以节约灌溉用水18.8%、节约用肥33.3%、节约用药21.3%。上述结果表明:土壤熏蒸消毒结合使用水肥菌/药一体化产品和技术,可以节水、节肥、节药,显著降低设施番茄各类病害的发生,提高番茄产量,实现节本增效。

为探究茉莉酸甲酯（Methyl Jasmonate，MeJA）诱导辣椒抗青枯病效应与活性氧代谢相关酶的关系，以辣椒易感青枯病品种‘粤红1号’和抗青枯病品种‘辛香8号’幼苗为试验材料，在0.1 mmol ? L-1 MeJA喷雾处理后12、24、48、72和96 h接种青枯劳尔氏菌（Ralstonia solanacearum），对其进行青枯病病情指数与活性氧代谢相关酶——超氧化酶歧化酶（Superoxide Dismutase，SOD）、过氧化氢酶（Catalase，CAT）、过氧化物酶（Peroxidase，POD）和抗坏血酸过氧化物酶（Ascorbate Peroxidase，APX）活性以及丙二醛（Malondialdehyde，MDA）含量测定及相互关系的分析。结果表明：‘粤红1号’和‘辛香8号’的病情指数随喷MeJA处理时间的推移表现为先降后升，但都低于对照；而诱导效果则相反，MeJA处理对两个辣椒品种幼苗抗性的最适诱导时间均为接种前48 h。接种后0 ~ 96 h，MeJA喷雾处理的辣椒幼苗叶片SOD、CAT、POD和APX酶活性均显示先升后降的趋势，且明显高于对照，接种后24 ~ 48 h达到最高，而MDA含量则明显低于对照。因此，MeJA可诱导辣椒幼苗抗青枯病，其实现途径可能与提高活性氧代谢相关酶活性和缓解膜脂过氧化有关。