Grafting is an effective technique for increasing the resistance of vegetables to biotic and abiotic stresses. It has been widely applied to produce solanaceous and melon vegetables. Temperature is an important external factor affecting graft formation. However, the molecular mechanism by which external ambient temperature affects tomato graft formation remains unclear. In this study, we demonstrated that elevating ambient temperature during grafting to 35 °C for more than 24 h after grafting accelerated vascular reconnection. We generated self- or heterografted combinations between phyB1B2 and pif4 loss-of-function mutant and wild-type plants, and were mutants unresponsive to graft formation at elevated ambient temperature. In addition, elevated ambient temperature induced SlPIF4 expression during grafting. SlPIF4 directly binds the promoters of auxin biosynthesis genes SlYUCCAs and activates their expression. Further investigation revealed auxin accumulation in the graft junction under elevated ambient temperature. The results illuminate the mechanism by which the PHYB-PIF4-auxin module promotes tomato graft formation in response to elevated ambient temperature.

Grafting is a common agricultural technique widely used in horticulture plants to improve stress tolerance, increase yield and improve quality. However, the biochemical processes underlying graft healing, especially the temporal dynamics and specific roles of polyphenolic metabolites, remain largely unknown. Polyphenols, widely present in plants, possess many biological activities, including antioxidant, antibacterial and anti-inflammatory properties. Temporal-resolution metabolomics, a powerful tool for studying metabolite dynamics over time, offers insights into the metabolic changes during this critical phase. To better understand this process, internodes above and below the graft site were harvested from 12 time points after grafting in both non-grafted and grafted peppers for polyphenolic metabolism analyses. In this study, we describe the accumulation pattern of 432 polyphenol metabolites. By comparing with the control group, nine polyphenolics were identified that responded to graft healing. The high temporal-resolution metabolomics reported here provides a basic resource for future functional study to unravel the genetic control of pepper graft development.

Graft healing involves a series of cytological and molecular events including wound responses, callus formation and vascular bundle remodelling. Hormones are important signalling molecules regulating plant development and responses to environmental stimuli. However, the detailed dynamics of phytohormones in graft healing remain elusive. In this research, internodes above and below the graft site were harvested from 0 to 168 h after grafting (HAG), and liquid chromatography tandem mass spectrometry (LC-MS/MS) was used to determinate jasmonic acid, auxin, cytokinin, ethylene, salicylic acid, abscisic acid and gibberellin levels during the graft healing process. Uniform manifold approximation and projection (UMAP) and k-means analyses were performed to explore hormone spatio-temporal dynamics. We found the stage-specific and asymmetric accumulation of phytohormones in the tomato graft healing process. At the early healing stage (before vascular bundle reconnection), IAA, cZ, ABA, JA and SA mainly accumulated above the graft site, while tZ and ACC mainly accumulated below the graft site. MEIAA, ICAld and IP mainly accumulated at the later stage. Comminated with the healing process, we suggested that JA is mainly involved in wound responses, IAA is beneficial to the formation of callus and vascular cell development, tZ promotes cell division, and IP is linked to vascular bundle remodelling. In addition, expression of JA-related genes SlMYC2 and SlJAZ2, IAA-related gene SlIAA1, tZ-related genes SlHP2 and SlRR8, and IP-related gene SlRR9 correlated with hormone accumulation. The findings provide important information about the hormones and genes involved in the tomato graft healing process.

Lateral roots (LRs) receive signals from the inter-root environment and absorb water and nutrients from the soil. Auxin regulates LR formation, but the mechanism in tomato remains largely unknown. In this study, ‘Ailsa Craig‘ tomato LRs appeared on the third day and were unevenly distributed in primary roots. According to the location of LR occurrence, roots were divided into three equal parts: the shootward part of the root (RB), the middle part of the root (RM), and the tip part of the root (RT). Transverse sections of roots from days 1 to 6 revealed that the number of RB cells and the root diameter were significantly increased compared with RM and RT. Using roots from days 1 to 3, we carried out transcriptome sequencing analysis. Identified genes were classified into 16 co-expression clusters based on K-means, and genes in four associated clusters were highly expressed in RB. These four clusters (3, 5, 8, and 16) were enriched in cellulose metabolism, microtubule, and peptide metabolism pathways, all closely related to LR development. The four clusters contain numerous transcription factors linked to LR development including transcription factors of LATERAL ORGAN BOUNDRIES (LOB) and MADS-box families. Additionally, auxin-related genes GATA23, ARF7, LBD16, EXP, IAA4, IAA7, PIN1, PIN2, YUC3, and YUC4 were highly expressed in RB tissue. Free IAA content in 3 d RB was notably higher, reaching 3.3–5.5 ng/g, relative to RB in 1 d and 2 d. The LR number was promoted by 0.1 μM of exogenous IAA and inhibited by exogenous NPA. We analyzed the root cell state and auxin signaling module during LR formation. At a certain stage of pericycle cell development, LR initiation is regulated by auxin signaling modules IAA14-ARF7/ARF19-LBD16-CDKA1 and IAA14-ARF7/ARF19-MUS/MUL-XTR6/EXP. Furthermore, as a key regulatory factor, auxin regulates the process of LR initiation and LR primordia (LRP) through different auxin signaling pathway modules.

海南夏季高温、高湿、台风、暴雨、水涝、病虫草害等不良因素严重影响苦瓜嫁接苗成活率和质量,技术集成创新应用,已取得显著效果.

Aiming at the problem of uneven distribution of solid inoculants directly added to the seedling substrate in the current production process of functional seedling substrates, based on a two-step compounding method, the mixing of γ-polyglutamic acid as inoculant carrier with traditional substrates was carried out. Single factor test and response surface analysis test were used to investigate the effects of carrier addition, seedling substrate moisture content, mixing speed and mixing time on the uniformity of Bacillus velezensis in seedling matrix. The results showed that the optimal mixing process parameters for the preparation of functional seedling substrates were as follows: The addition amount of γ-polyglutamic acid was 5.6 g/L, the seedling substrate moisture content was 35%, the mixing speed was 42 r/min, and the mixing time was 333 s. Under the above conditions, the coefficient of variation of B. velezensis was 4.59%. The optimized functional seedling matrix had no significant difference in bulk density and porosity with the traditional matrix, and the water-holding pore and maximum water-holding capacity of the matrix were increased by 5.68% and 7.92%, respectively.

基质水分吸持特性直接影响蔬菜穴盘苗生长发育及整齐度,配制适宜的基质是潮汐式育苗的一个关键科学问题.为了探究湿润剂对基质水分吸持的作用,该研究选用3种湿润剂(SP、GY-S903、KT),设置0、0.15、0.30、0.60 mL/L共4个添加量,研究湿润剂添加对育苗基质水分吸收、蒸散和白菜穴盘苗生长的作用.结果表明:添加湿润剂处理与未添加湿润剂的对照处理相比,基质吸水量提高23.90％～74.70％,吸水高度提高46.03％～94.28％,吸水速率增加60.57％～116.26％,且湿润剂添加量越高,基质吸水能力越强;相对于不添加湿润剂处理,添加湿润剂显著提高了基质相对含水量和基质水分蒸散速率(P<0.05);湿润剂添加减小了潮汐床箱中不同位点穴盘基质吸水差异,吸水量变异系数降低9.01个百分点.进一步测定湿润剂添加后白菜穴盘苗生长发育参数,发现适量湿润剂对白菜穴盘苗生长无不良影响.研究结果为改善育苗基质水分吸持特性提供了依据.

嫁接可有效克服茄果类蔬菜黄萎病(Verticillium dahliae)、 青 枯 病(Ralstonia solanacearum)、 疫 病(Phytophthora capsici Leonian)、根结线虫等土传病害,增强植株对低温、高温、干旱、盐胁迫、水涝等非生物逆境的耐性,提高根系对水分和养分的吸收能力,增加产量,改善品质.

烯效理(Uniconazole,S3307)作为赤霉素抑制剂,常用于调控植物生长发育,但是否影响嫁接愈合,目前尚不清楚.以番茄'硬粉8号'为接穗材料,以'砧爱1号'为砧木材料,于播种后15和21d分两次叶面喷施0.25 mg·L-1烯效唑,结果发现烯效唑处理抑制了接穗和砧木幼苗生长,至播种后27 d嫁接时,株高分别较去离子水处理的对照降低了 20.58％和12.75％;嫁接后12-72h,烯效唑处理降低了嫁接接合部GA15和GA8含量,促进了 GA3、IAA、MEIAA、ICAld、TRP和iP7G积累;增加了接合部上方与下方IAA1相对表达量的差异,上调了接合部上方G420ox1、IAA1和4RR17的相对表达量,下调了接合部下方GA20ox1和ARR17相对表达量.嫁接后6～168 h,烯效唑处理提高了嫁接接合部TMO6和CyclinB1;2的相对表达量,以及接合部上方WIND1、WOX4和VND7的表达量;使嫁接接合部上方与下方IAA1、ARR17、WIND1、TMO6、WOX4和VND7的表达更早趋于一致,木质部和韧皮部连接提前.另外,烯效唑处理的幼苗嫁接接合部于嫁接后72 h开始连接,嫁接后96～120 h木质部和韧皮部连接基本完成,早于对照24 h.表明番茄幼苗嫁接前叶面喷施烯效唑可有效调节嫁接接合部内源激素水平,促进嫁接愈合.

绿叶类蔬菜主要以柔嫩的绿叶、叶柄和嫩茎为食用部位,种类较多,世界各国栽培的绿叶类蔬菜约15个科40余种,我国栽培的绿叶类蔬菜约有13个科21种.根据绿叶类蔬菜对温度条件的要求,可分为两大类:一类要求冷凉的气候,较耐寒,生长适温15～20 ℃,如菠菜、茼蒿、叶菾菜、芹菜、芫荽、茴香、莴苣、苦菜、菊苣、冬寒菜、荠菜、叶用莴苣(生菜)等;另一类喜温暖,较耐热,生长适温20～25 ℃,如苋菜、蕹菜(空心菜)、番杏、落葵(木耳菜)、紫苏、紫背天葵、罗勒等.

按照农业生物学分类,白菜类蔬菜主要包括白菜亚种和大白菜亚种.白菜亚种又包括5个变种,即普通白菜变种、乌塌菜变种、菜薹变种、紫菜薹变种和薹菜变种;大白菜亚种包括散叶变种、半结球变种、花心变种和结球变种.白菜类蔬菜以柔嫩的叶片、叶球或花薹为食用器官,生长期间要求温和的气候环境,耐寒而不耐热,生长速度快,对氮肥需求量大.

以中杂302为试材,将番茄穴盘苗生长发育分为5个阶段(Ⅰ:播种至出苗;Ⅱ:出苗至子叶平展;Ⅲ:子叶平展至二叶一心;Ⅳ:二叶一心至三叶一心;Ⅴ:三叶一心至四叶一心),分段设定9个营养液浓度组合,研究潮汐灌溉条件下营养液浓度分段设定对番茄穴盘苗生长发育、养分积累量及利用率的影响.结果表明:在第Ⅰ阶段,灌溉1.0×营养液,番茄穴盘苗出苗率最高,播种后第7天比清水对照提高了7.71百分点,显著高于其他处理;当营养液浓度设定为Ⅰ阶段0.25×、Ⅱ阶段0.25×、Ⅲ阶段0.5×、Ⅳ阶段1.5×、Ⅴ阶段1.5×时(处理9),番茄穴盘苗第Ⅴ阶段的株高、茎粗、叶面积、总根长、根体积、根表面积、根平均直径、茎叶及根鲜质量和干质量、壮苗指数等指标最优,穴盘苗干质量增长速率最高;N、P、K的吸收积累量最高,分别为15.8、10.1、21.0 mg· 株-1,利用率分别为14.35％、6.10％、15.92％.

茄果类蔬菜主要包括番茄、辣椒和茄子.每种蔬菜又分为若干类型,番茄根据用途分为鲜食番茄和加工番茄,根据生长习性分为无限生长型和有限生长型,根据果实大小分为大果型(单果质?量≥150 g)、中果型(单果质量100～149 g)和小果型(单果质量≤100 g),根据颜色分为大红、粉红、黄色、绿色、紫色番茄等;辣椒根据果实形状可分为樱桃椒、圆锥椒、簇生椒、线椒和甜椒;茄子可分为圆茄、长茄和矮生茄.

植物根际促生菌是一类生活在植物根际,或附着于根系表面,或生活在植物体内的微生物,能够促进植物对矿质养分的吸收利用,抑制和拮抗病原菌生长,分泌植物生长激素,促进植物生长(穆文强等,2022).目前,国内已商品化的植物根际促生菌菌剂有液态发酵和固态发酵两种生产方式.液态发酵相比于固态发酵具有速度快、周期短、产量高、均匀性好、便于机械化操作、发酵过程易于控制、菌体可与培养基分离、菌量密度高等优点.笔者对植物根际促生菌菌剂液态发酵原料的选择、生产工艺、质量要求等进行介绍,并总结植物根际促生菌菌剂在蔬菜苗期的应用方法和效果,以期为植物根际促生菌菌剂的制备和应用提供参考.

甘蓝类蔬菜属于十字花科,主要包括结球甘蓝、羽衣甘蓝、抱子甘蓝、球茎甘蓝、芥蓝、花椰菜(白菜花、松花菜)、青花菜等,叶片蓝绿色、肥厚、被有蜡粉,叶脉明显,喜冷凉湿润气候,不耐高温干旱,属于绿体春化型低温长日照作物,以叶片、叶球、短缩球茎、花薹、侧芽或花蕾为食用器官.我国甘蓝类蔬菜以结球甘蓝栽培面积最广,总产量最高,种植面积约90万hm2(杨丽梅 等,2021).其次是花椰菜,种植面积约52.01万hm2(单晓政 等,2019).甘蓝类蔬菜根系发达,再生能力较强,适于育苗移栽,但苗期对环境条件要求高,易徒长.笔者对甘蓝类蔬菜新优品种以及基质配制、穴盘选型、苗期环境分段管理、成苗贮运等集约化育苗关键技术进行总结,并针对甘蓝类蔬菜幼苗不耐盐、易徒长和虫害重等问题,提出了灌溉水质、幼苗株型调控、小菜蛾综合防治等核心技术.

土壤连作障碍严重制约瓜类蔬菜优质丰产高效生产.嫁接可有效克服瓜类蔬菜枯萎病(Fusarium oxysporum Schltdl.)、根 腐 病(Monosporascus cannonballus Pollack & Uecker)、疫病(Phytophthora capsici Leonian)、黄 萎 病(Verticillium dahlia Kleb.)、黑腐病(Phomopsis sclerotiodes Kesteren)、根结线虫等土传病害,增强植株对病毒病(CMV、WMV-II、PRSV、ZYMV、MNSV)的抗性,缓解低温、干旱、弱光、盐胁迫、高湿、重金属胁迫伤害,提高根系水分和养分吸收能力,减少化学农药和化学肥料施用量,增加产量,改善品质.

葱蒜类蔬菜是百合科(Liliaceae)葱属(Allium)中以嫩叶、假茎、鳞茎、花薹为食用器官的草本植物,包括大蒜(A. sativum L.)、葱(A. fistulosum L.)、韭菜(A. tuberosum Rottl. ex Spr.)、洋葱(A. cepa L.)、韭葱(A. porrum L.)、细香葱(A. schoenoprasum L.)、胡葱(A. ascalonicum L.)和薤(A. chinensis G. Don),多具辛辣味,有杀菌消炎、增进食欲的作用,是佐餐佳品.葱蒜类蔬菜多数原产自亚洲西部大陆性气候区,四季和昼夜温差较大、空气干燥、土壤湿度变化大等气候特点,使葱蒜类蔬菜形成鲜明的生物学特征:短缩的茎盘,喜湿的根系,耐旱的叶形,具有贮藏功能的鳞茎或假茎,抗寒耐热.葱蒜类蔬菜在我国栽培历史悠久,其中葱、大蒜、韭菜、洋葱栽培尤为普遍.我国也是葱蒜类蔬菜生产和出口大国,2018年总播种面积206.7万hm2,其中大蒜80万hm2、大葱60万hm2、洋葱20万hm2(樊继德等,2020).大蒜以鳞茎(蒜瓣)直播为主,葱、洋葱、韭菜则可采用集约化育苗移栽(图1).

重庆市地处我国西南地区,全市蔬菜年播种面积达78.59万hm2(1? 178.8万亩),年产量2? 113.5万t,年种苗需求量约80亿株,集约化育苗占比约为15％.据粗略统计,重庆市现有蔬菜年育苗量在1? 000万株以上的企业5个,年育苗量500万～ 1? 000万株的企业约50个,年育苗量500万株以下的企业约160个,蔬菜集约化育苗技术应用和产业化发展较快,并初步形成了以蔬菜集约化育苗企业为核心的蔬菜产业社会化服务格局.

【Objective】The root-cutting grafting seedlings and top-pinching double-stem grafting seedlings or multi-stem grafting seedlings have been widely used in tomato cultivation, which have significant effects on high yield. Understanding the mechanism of root-cutting and top-pinching on tomato graft healing could provide the theoretical basis for tomato grafting production.【Method】Using ‘YingFen No. 8’ as scion and ‘ZhenAi No. 1’ as rootstock, the grafting healing process, survival rate and xylem connectivity of tomato after root-cutting and top-cutting were observed, and the contents of auxin and cytokinin as well as the expressions of healing related genes in the grafted part were measured.【Result】Root-cutting and top-pinching inhibited the expression of xylem differentiation gene VND7 above the graft union, and significantly delayed xylem remodeling. The root-cutting treatment significantly decreased the contents of trans-Zeatin riboside (tZR) and trans-Zeatin (tZ) at 12 and 72 hours after grafting, as well as the contents of indole-3-acetic acid (IAA), methyl indole-3-acetate (ME-IAA) and indole-3-carboxaldehyde (ICAld) at 12 hours after grafting. The contents of IAA and ME-IAA at 12 hours after top-pinching grafting were significantly lower than those of the control and root-cutting treatment, and the expression level of the phloem differentiation related gene NEN4 at 3 and 12 hours after grafting was down-regulated. Root-cutting or top-pinching down-regulated the expression levels of cell division related genes Histone H4 and SlcycB1-4 above the graft union at 3-48 hours after grafting. Under root-cutting and top-pinching treatment, the contents of IAA and ME-IAA in grafting union were significantly lower than those under root-cutting treatment, and the contents of tZR and tZ and xylem connectivity were significantly lower than those under top-pinching treatment. The application of 10 mmol∙L-1 IAA and 10 mmol∙L-1 6-BA at the grafted union after top-pinching and root-cutting could significantly promote the xylem remodeling of grafted seedlings.【Conclusion】In conclusion, root-cutting and top-pinching could reduce the accumulation of cytokinin and auxin, down-regulate the expression of genes related to healing, reduce xylem transduction capacity, and delay the process of tomato grafting healing.

瓜类蔬菜是葫芦科中以瓠果为食用器官的栽培种群,一年生或多年生攀缘性、短日照草本植物,包括西瓜、甜瓜、黄瓜、冬瓜、苦瓜、南瓜、瓠瓜、丝瓜、佛手瓜等.瓜类蔬菜在全国各地均有大面积栽培,我国2019年西瓜种植面积147万hm2,产量6086万t(刘文革,2021);2018年甜瓜收获面 积、产量分别为35.45万hm2和1272.73万t(王娟娟 等,2020);冬瓜年播种面积33.33万hm2(谢大森 等,2020);"十三五"期间黄瓜年均播种面积122.97万hm2,产量6623.08万t(张圣平 等, 2021).瓜类蔬菜喜温暖,不耐低温和霜冻,对温周期和光周期较敏感,低温和短日照条件有利于花芽分化和雌花的形成,根系发达.为了提早采收和降低成本,传统上以育苗移栽为主.