To investigate the importance of shoot-to-root communication in modulating tissue phytohormone balance as the soil dries, root and leaf hormonal profiles were determined in soybean plants (Glycine max L. Merr. cv. Siverka) exposed to factorial girdling (achieved surgically on Day 0 by excising the phloem with a sharp razor blade thereby disrupting basipetal hormone transport) and soil drying treatments. Plants were randomized into 2 groups: girdled and intact plants, and each girdled group was further separated into two groups: well-watered and soil drying. Thus the experiment was a two (± girdling) x two (± soil drying) factorial experiment. Within 26 h while the soil was still moist, girdling increased root ACC (by 11-fold) and decreased root ABA concentrations (by 28 %), decreased foliar iP, tZ and GA₃ concentrations (by up to 90 %), and increased foliar ABA and JA concentrations (by 1.6- and 4.9-fold respectively) compared to intact plants, but only leaf ABA concentration correlated with partial stomatal closure. Two days of soil drying increased root ABA and JA concentrations in intact plants, and both hormones significantly decreased in roots of girdled plants compared to intact plants. Soil drying increased foliar iP, ABA, JA and SA concentrations by 1.3-, 2.5-, 1.3- and 1.4-fold respectively compared to well-watered intact plants by the end of the experiment, but girdling prevented this foliar iP, ABA, JA accumulation compared to droughted intact plants. Thus, girdling affects the co-ordination of root and leaf phytohormone concentrations such as JA and ABA, which may transiently modulate stomatal closure. However, leaf ABA concentration varied consistently with root ABA concentration across all treatments, and explained more of the variation in stomatal conductance than any other hormone or leaf water potential.

为了研究当土壤干燥时，芽到根的交流在调节组织植物激素平衡中的重要性，在暴露于阶乘环切（通过外科手术实现）的大豆植物（Glycine max L. Merr. cv. Siverka）中测定根和叶激素谱第 0 天，用锋利的刀片切除韧皮部，从而破坏基叶激素运输）和土壤干燥处理。植物被随机分为2组：环带和完整植物，每个环带组进一步分为两组：充分浇水和土壤干燥。因此，该实验是一个二（± 环剥）×二（± 土壤干燥）因子实验。在土壤仍然潮湿的 26 小时内，环剥增加了根系 ACC（11 倍）并降低根系 ABA 浓度（28%），降低叶面 iP、tZ 和 GA₃浓度（高达 90%），并且与完整植物相比，叶 ABA 和 JA 浓度增加（分别增加 1.6 倍和 4.9 倍），但只有叶 ABA 浓度与部分气孔关闭相关。两天的土壤干燥增加了完整植物的根 ABA 和 JA 浓度，与完整植物相比，环带植物根中的两种激素显着降低。到实验结束时，土壤干燥使叶面 iP、ABA、JA 和 SA 浓度分别比浇水充足的完整植物增加了 1.3、2.5、1.3 和 1.4 倍，但环剥阻止了这种叶面 iP、ABA、JA与干旱的完整植物相比积累。因此，环剥影响根和叶植物激素浓度的协调，例如 JA 和 ABA，这可能会暂时调节气孔关闭。然而，