Agricultural Research Council Unit of Experimental Agronomy, Department of Agriculture, University of Oxford, Oxford, England.
Plant Physiol. 1966 Apr;41(4):725-30. doi: 10.1104/pp.41.4.725.
Measurements were made of the transport of 2,4-dichlorophenoxyacetic acid-(14)C (2,4-D) through segments cut from the region of the distal abscission zone in young and old primary leaves of Phaseolus vulgaris L. When old leaves were used basipetal transport of 2,4-D in segments including pulvinar tissue, abscission zone, and petiolar tissue was much less than in wholly petiolar segments. In both young and old plants, segments consisting entirely of pulvinar tissue transported 2,4-D basipetally at a velocity about half that in petiolar tissue. At both ages the flux of 2,4-D through pulvinar tissue was less than that through petiolar tissue. In segments from old leaves the flux through pulvinar tissue was much less than in young plants; the flux through petiolar tissue changed little with age. There was no change with age in the velocity of basipetal transport. The distribution of (14)C along segments including the abscission zone showed no marked discontinuity. It was concluded that the pulvinus limited the basipetal movement of 2,4-D through segments from old leaves which included both pulvinar and petiolar tissue, but there was no evidence that the abscission zone itself was a barrier to auxin transport.
测量了 2,4-二氯苯氧乙酸-（14）C（2,4-D）在菜豆年轻和年老的初级叶片远轴脱落区切段中的运输。当使用老叶时，包括叶枕组织、脱落区和叶柄组织的切段中 2,4-D 的向基运输明显少于完全是叶柄的切段。在年轻和年老的植物中，完全由叶枕组织组成的切段以大约是叶柄组织的一半的速度向基运输 2,4-D。在两个年龄阶段，2,4-D 通过叶枕组织的通量都小于通过叶柄组织的通量。在老叶的切段中，叶枕组织的通量远小于年轻植物；叶柄组织的通量随年龄变化不大。向基运输的速度没有随年龄变化而变化。包括脱落区的切段中（14）C 的分布没有明显的不连续性。结论是叶枕限制了包括叶枕和叶柄组织的老叶切段中 2,4-D 的向基运动，但没有证据表明脱落区本身是生长素运输的障碍。
