...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Protoplasma: An International Journal of Cell Biology >An investigation of the role of solutes in the xylem sap and in the xylem parenchyma as the source of root pressure
【24h】

An investigation of the role of solutes in the xylem sap and in the xylem parenchyma as the source of root pressure

机译：溶质在木质部汁液和木质部薄壁组织中作为根压源的作用的研究

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Solute osmotic potentials (psi(x)) in the vessels of hydroponically grown maize roots were measured to assess the osmotic-xylem-sap mechanism for generating root pressure (indicated by guttation). Solutes in vessels were measured in situ by X-ray microanalysis of plants frozen intact while guttating. Osmotic potentials outside the roots (psi(o)) were changed by adding polyethylene glycol to the nutrient solution. Guttation rate fell when psi(o) was decreased, but recovered towards the control value during 3-5 days when psi(o), was greater than or equal to -0.3 MPa, but not when psi(o) was equal to -0.4 MPa. In roots stressed to psi(o) = -0.3 MPa, psi(x) was always more positive than psi(o) and psi(x) changed only slightly (ca. 0.05 MPa). Thus the adjustment in the roots which increased root pressure cannot be ascribed to psi(x), contradicting the osmotic-xylem-sap mechanism. An alternative driving force was sought in the osmotic potentials of the vacuoles of the living cells (psi(nu)), which were analysed by microanalysis and estimated by plasmolysis. psi(nu) showed larger responses to osmotic stress (0.1 MPa). Some plants were pretreated with abundant KNO3 in the nutrient solution. These plants showed very large adjustments in psi(nu) (0.4 MPa) but little change in psi(x), (0.08 MPa). They guttated by 4 h after psi(o) was lowered to -0.4 MPa. It is argued that turgor pressure of the living cells is a likely alternative source of root pressure. Published evidence for high solute concentrations in the xylem sap is critically assessed. [References: 41]
机译：测量了水培生长的玉米根部容器中的溶质渗透势（psi（x）），以评估产生根压的渗透液木质部汁液机制（通过点胶表示）。通过X射线显微分析原位冷冻的植物的肠道原位测量其溶质。通过在营养液中添加聚乙二醇来改变根部外的渗透势（psi（o））。当psi（o）降低时，胶凝率下降，但当psi（o）大于或等于-0.3 MPa时，在3-5天内恢复到控制值，但在psi（o）等于-0.4 MPa时没有回胶MPa。在压力为psi（o）= -0.3 MPa的根中，psi（x）总是比psi（o）更强，而psi（x）的变化很小（约0.05 MPa）。因此，根部增加根部压力的调节不能归因于psi（x），与渗透木质部树液的作用机理相反。在活细胞液泡（psi（nu））的渗透势中寻找另一种驱动力，通过微分析对其进行分析，并通过纤溶酶对其进行评估。 psi（nu）对渗透压（0.1 MPa）表现出更大的响应。在营养液中用丰富的KNO3预处理了一些植物。这些植物的psi（nu）（0.4 MPa）调整幅度很大，而psi（x）（0.08 MPa）的变化很小。在psi（o）降至-0.4 MPa后的4小时内，它们开始蠕动。有人认为，活细胞的膨压是根压的替代来源。严格评估了木质部汁液中高溶质浓度的公开证据。 [参考：41]

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号