Environments with short growing seasons and variable climates can have soil temperatures that are suboptimal for chilling-sensitive crops. These conditions can adversely affect root growth and physiological performance thus impairing water and nutrient uptake. Four greenhouse trials and a field study were conducted to investigate if rootstocks can enhance tomato performance under suboptimal soil temperatures (SST). In a controlled greenhouse environment, we exposed four commercial rootstocks (Estamino, Maxifort, RST-04-106-T, and Supernatural) grafted with a common scion (cv. BHN-589) to optimal (mean: 24°C) and SST (mean: 13.5°C) and compared their performance with the non-grafted BHN-589 cultivar. Several root and shoot physiological traits were evaluated: root hydraulic conductivity and conductance, root anatomy, leaf gas exchange, leaf δ¹³C, shoot C and N, and biomass. Under field conditions, the same five phenotypes were evaluated for canopy growth, normalized difference vegetation index (NDVI), leaf nutrients, biomass, and yield. Under SST, root hydraulic conductivity (Lp) and conductance (K_R), stomatal conductance (g_s), and plant biomass decreased. Hydrostatic Lp decreased more than osmotic Lp (Lp^∗_hyd: 39–65%; Lp^∗_os: 14–40%) and some of the reduced conductivity was explained by the increased cortex area of primary roots observed under SST (67–140%). Under optimal soil temperatures, all rootstocks conferred higher g_s than the non-grafted cultivar, but only two rootstocks maintained higher g_s under SST. All phenotypes showed greater reductions in shoot biomass than root biomass resulting in greater (∼20%) root-to-shoot ratios. In the field, most grafted phenotypes increased early canopy cover, NDVI, shoot biomass, and fruit yield. Greenhouse results showed that Lp^∗_os may be less affected by SST than Lp^∗_hyd and that reductions in Lp may be offset by enhanced root-to-shoot ratios. We show that some commercial rootstocks possess traits that maintained better rates of stomatal conductance and shoot N content, which can contribute toward better plant establishment and improved performance under SST.

生长季节短，气候多变的环境中，土壤温度对于敏感的农作物而言可能不是最理想的。这些条件可能会对根生长和生理性能产生不利影响，从而损害水和养分的吸收。进行了四项温室试验和一项田间研究，以研究砧木是否可以在土壤温度不理想的条件下提高番茄的性能。在受控的温室环境中，我们将四种嫁接有普通接穗（cv。BHN-589）的商业砧木（Estamino，Maxifort，RST-04-106-T和Supernatural）暴露于最佳温度（平均温度：24°C）和SST （平均温度：13.5°C），并将其性能与未嫁接的BHN-589品种进行比较。评价了几种根和茎的生理特性：根的水力传导率和电导率，根的解剖结构，叶片气体交换，叶片的δ¹³ C，碳和氮，以及生物量。在田间条件下，对相同的五种表型进行了冠层生长，归一化差异植被指数（NDVI），叶片养分，生物量和产量的评估。在SST下，根部水力传导率（p）和电导（ķ_R），气孔导度（G_s），植物生物量减少。静水压力p 下降多于渗透 p （p^∗ _hyd：39–65％；p^* _os：14–40％），并且电导率降低的部分原因是在SST下观察到的初生根皮层面积增加（67–140％）。在最佳土壤温度下，所有砧木均具有较高的品质G_Ş比非嫁接品种，但只有两个砧木保持较高G_š SST下。所有表型均显示出茎生物量的减少量大于根生物量，从而导致较高的根茎比（约20％）。在田间，大多数嫁接表型增加了早期冠层覆盖，NDVI，枝条生物量和果实产量。温室结果表明p^∗ _os受SST的影响可能小于p^* _hyd和减少p可以通过提高根与拍摄比来抵消。我们表明，一些商业砧木具有保持更好的气孔导度和芽N含量的性状，可以促进更好的植株生长和SST条件下的改良性能。