TRANSPORT OF RB AND SR TO THE EAR IN MATURE, EXCISED SHOOTS OF WHEAT - EFFECTS OF TEMPERATURE AND STEM LENGTH ON RB REMOVAL FROM THE XYLEM
TRANSPORT OF RB AND SR TO THE EAR IN MATURE, EXCISED SHOOTS OF WHEAT - EFFECTS OF TEMPERATURE AND STEM LENGTH ON RB REMOVAL FROM THE XYLEM
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DOI：
10.1007/bf00010409
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发表时间：
1991-04-01
期刊：
影响因子：
4.9
通讯作者：
FELLER, U
中科院分区：
文献类型：
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作者：
KUPPELWIESER, H;FELLER, U
小麦（Triticum aestivum L.）CV.在开花后切除在田间生长的芽，并在实验室中在2mM RbCl +2mM SrCl 2中静置孵育72小时。 锶是一种韧皮部不移动，木质部移动的元素，并指示木质部汁液在植物中的分布。 铷易于在韧皮部中运输，并且就植物内的再分配而言，其行为类似于高移动的K，尽管Rb不能在生理学或生物化学上替代K。 穗部锶含量受茎长和汽割（韧皮部中断）的影响不大。 另一方面，铷在茎中积累。 5厘米的花序梗长度是足够的，以减少超过50%的木质部中的Rb浓度在25 ℃。 只有少量的Rb到达穗后，通过20厘米的茎没有节点，这种运输被阻止蒸汽环剥。 Rb进入穗的显着通量观察与旗叶叶片和穗之间的血管连接的拍摄。 我们的研究结果表明，Sr的运输与蒸腾流，而Rb迅速消除木质部，并通过韧皮部到达穗。 从木质部中去除Rb的最佳温度为35 ℃左右。 节点可能会进一步做出贡献，但不是这种重新分配的先决条件。 所观察到的转移过程可以允许溶质通过成熟谷物的木质部和韧皮部的特定运输，并可能是影响田间养分经济的重要因素。
Wheat (Triticum aestivum L. cv. 'Arina') shoots grown in the field were excised post-anthesis and incubated in the laboratory for 72 h standing in 2 mM RbCl + 2 mM SrCl2. Strontium is a phloem-immobile, xylem-mobile element and indicates the distribution of the xylem sap in the plant. Rubidium is easily transported in the phloem and behaves similarly to the highly mobile K as far as the redistribution within the plant is concerned, although Rb cannot substitute physiologically or biochemically for K. The Sr contents in the ear were hardly affected by stem length or by steam-girdling (phloem-interruption). Rubidium on the other hand accumulated in the stem. A peduncle length of 5 cm was sufficient to decrease the Rb concentration in the xylem by more than 50% at 25-degrees-C. Only a minor quantity of Rb reached the ear after passing through 20 cm of stem without nodes and this transport was prevented by steam-girdling. A remarkable flux of Rb into the ear was observed in shoots with a vascular connection between the flag leaf lamina and the ear. Our results suggest that Sr was transported with the transpiration stream, while Rb was rapidly eliminated from the xylem and reached the ear via the phloem. The temperature optimum for the removal of Rb from the xylem was around 35-degrees-C. The nodes may further contribute, but are not prerequisites for this redistribution. The observed transfer processes could allow a solute specific transport via the xylem and phloem of maturing cereals and may be an important factor influencing the nutrient economy in the field.