2，4-D对麦苗的刺激、抑制和致瘤效应的研究

 低浓度2，4-D溶液作用于麦苗的不同部位，产生不同的生理效应。以1.5ppm的2，4-D溶液喷于麦苗茎、叶，对小麦生长有刺激作用，但根部不形成瘤状物；如以同样浓度的2，4-D溶液浇根，麦苗根部形成瘤状物，但麦苗植株生长受到抑制。用抗药性标记的田菁茎瘤菌（Azorhizobium caulinodans）接种，证明在30%左右的麦瘤中有该菌进入，但这种麦瘤测不出固氮酶活性，说明麦瘤中少量茎瘤菌是随机性的被动进入，也没有与小麦植株建立共生关系。

A STUDY ON STIMULATION, INHIBITION AND NODULATION OF WHEAT SEEDLINGS BY 2, 4-D

A lowly-concentrated solution of 2,4-D acting on different parts of Wheat seedlings produced different physiological effects. These experimental results are discussed in this paper. 1.5ppm of 2.4-D solution, when sprayed on stems and leaves of wheat seedlings, gave the stimulation effect on their growth, but no nodules formed in the roots. In case of pouring wheat roots with 2.4-D solution of the same concentration, the growth of wheat seedlings was inhibited, and at the same time, nodules formed in the roots of wheat seedlings. Inoculation with drugresistance marked Azorhizobium Caulinodans showed that 30% of nodules were infected by these bacteria. However, no nitrogenase activity in wheat nodules was determined. This illustrated that only a few Azorhizobium Caulinodans intruded into wheat nodules at random and passively, and no symbiotic relation was found between these bacteria and wheat plants.