Drought-tolerant tomato wild relatives and show heat-tolerant responses, but their use as rootstocks to enhance thermotolerance has not been examined. This study investigated the effects of heat stress on tomato plants grafted onto commercial ‘Maxifort’ and wild relatives and rootstocks in high tunnel, open-field and growth chamber experiments. Heat-tolerant ‘Celebrity’ and heat-sensitive ‘Arkansas Traveler’ cultivars were used as scions, and non-grafted (high tunnel, open-field) or self-grafted plants (growth chamber) were used as controls. The high tunnel and open-field experiments were conducted in the spring (March – June) and summer (June – September) for control and heat treatment, respectively, with daily high/low average temperatures of 27.5/19.0 °C and 33.2/22.5 °C in the high tunnel and 28.2/17.5 °C and 33.8/23.1 °C in the open-field. The growth chamber experiment was conducted at 38/30 °C (day/night) and 26/19 °C for the heat and control treatments, respectively, for 21 days. The shoot and root growth of and -grafted tomato plants were adversely affected by potential low graft compatibility resulting from interspecific grafting and their limited adaptability to the open-field soil environment, regardless of stress conditions. -grafted plants showed heat-sensitive responses in root biomass and architecture, leaf chlorophyll fluorescence, electrolyte leakage and relative water content depending on the environment, indicating its unsuitability as a rootstock under heat stress. On the other hand, plants grafted onto exhibited heat-tolerant responses in physiological aspects, including the gas exchange, leaf chlorophyll, carotenoid and amino acid in the growth chamber, fruit yield in the high tunnel, and chlorophyll fluorescence in both experiments. We suggest that could be utilized as effective breeding material for developing interspecific hybrid rootstocks with thermotolerance and increased graft compatibility between scion and rootstock to improve shoot and root growth of grafted plants.

中文翻译：

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探索潘氏茄和秘鲁茄作为砧木增强番茄植株耐热性的潜力

耐旱番茄野生近缘种并表现出耐热反应，但它们用作砧木以增强耐热性的用途尚未得到检验。本研究在高隧道、露天和生长室实验中研究了热应激对嫁接到商业“Maxifort”和野生近缘种以及砧木上的番茄植株的影响。使用耐热“名人”和热敏感“阿肯色旅行者”品种作为接穗，使用非嫁接（高隧道、露地）或自嫁接植物（生长室）作为对照。高坑实验和露天实验分别在春季（3-6月）和夏季（6-9月）进行控制和热处理，日高/低平均气温分别为27.5/19.0℃和33.2/22.5℃。高隧道中为 28.2/17.5 °C 和露天为 33.8/23.1 °C。生长室实验分别在 38/30 °C（白天/夜间）和 26/19 °C 下进行加热和对照处理，持续 21 天。无论胁迫条件如何，种间嫁接导致的潜在低嫁接相容性及其对露地土壤环境的有限适应性都会对嫁接番茄植株的芽和根生长产生不利影响。 -嫁接植物在根部生物量和结构、叶片叶绿素荧光、电解质泄漏和相对含水量方面表现出热敏感反应，这取决于环境，表明其不适合作为热胁迫下的砧木。另一方面，嫁接的植物在生理方面表现出耐热反应，包括生长室中的气体交换、叶片叶绿素、类胡萝卜素和氨基酸、高隧道中的果实产量以及两个实验中的叶绿素荧光。我们建议将其作为有效的育种材料，用于开发具有耐热性的种间杂交砧木，并增加接穗和砧木之间的嫁接相容性，以改善嫁接植物的芽和根的生长。