Data from: Testing the Münch hypothesis of long distance phloem transport in plants

Long distance transport in plants occurs in sieve tubes of the phloem. The pressure flow hypothesis introduced by Ernst Münch in 1930 describes a mechanism of osmotically generated pressure differentials that are supposed to drive the movement of sugars and other solutes in the phloem, but this hypothesis has long faced major challenges. The key issue is whether the conductance of sieve tubes, including sieve plate pores, is sufficient to allow pressure flow. We show that with increasing distance between source and sink, sieve tube conductivity and turgor increases dramatically in Ipomoea nil. Our results provide strong support for the Münch hypothesis, while providing new tools for the investigation of one of the least understood plant tissues.植物体内的长距离运输过程发生于韧皮部（phloem）的筛管（sieve tubes）中。1930年，恩斯特·明希（Ernst Münch）提出了压力流假说（pressure flow hypothesis），该假说描述了一种由渗透作用产生的压力差机制，可驱动糖类及其他溶质在韧皮部内移动，但该假说长期以来面临诸多重大挑战。其核心争议在于，包含筛板孔（sieve plate pores）在内的筛管导度是否足以支撑压力流的运行。本研究表明，随着源库间距离的增加，裂叶牵牛（Ipomoea nil）的筛管导度与膨压均显著升高。本研究结果为明希压力流假说提供了强有力的支持，同时也为研究目前认知最为薄弱的植物组织之一提供了全新的研究工具。