PDF(Pubmed)
Abstract：
OBJECTIVE: Cress seeds release allelochemicals that over-stimulate the elongation of hypocotyls of neighbouring (potentially competing) seedlings and inhibit their root growth. The hypocotyl promoter is potassium, but the root inhibitor was unidentified; its nature is investigated here.
METHODS: Low-molecular-weight cress-seed exudate (LCSE) from imbibed Lepidium sativum seeds was fractionated by phase partitioning, paper chromatography, high-voltage electrophoresis and gel-permeation chromatography (on Bio-Gel P-2). Fractions, compared with pure potassium salts, were bioassayed for effects on Amaranthus caudatus seedling growth in the dark for 4 days.
RESULTS: The LCSE robustly promoted amaranth hypocotyl elongation and inhibited root growth. The hypocotyl inhibitor was non-volatile, hot acid stable, hydrophilic and resistant to incineration, as expected for K+. The root inhibitor(s) had similar properties but were organic (activity lost on incineration). The root inhibitor(s) remained in the aqueous phase (at pH 2.0, 6.5 and 9.0) when partitioned against butan-1-ol or toluene, and were thus hydrophilic. Activity was diminished after electrophoresis, but the remaining root inhibitors were neutral. They became undetectable after paper chromatography; therefore, they probably comprised multiple compounds, which separated from each other, in part, during fractionation. On gel-permeation chromatography, the root inhibitor co-eluted with hexoses.
CONCLUSIONS: Cress-seed allelochemicals inhibiting root growth are different from the agent (K+) that over-stimulates hypocotyl elongation and the former probably comprise a mixture of small, non-volatile, hydrophilic, organic substances. Abundant components identified chromatographically and by electrophoresis in cress-seed exudate fitting this description include glucose, fructose, sucrose and galacturonic acid. However, none of these sugars co-chromatographed and co-electrophoresed with the root-inhibitory principle of LCSE, and none of them (in pure form at naturally occurring concentrations) inhibited root growth. We conclude that the root-inhibiting allelochemicals of cress-seed exudate remain unidentified.
METHODS: Low-molecular-weight cress-seed exudate (LCSE) from imbibed Lepidium sativum seeds was fractionated by phase partitioning, paper chromatography, high-voltage electrophoresis and gel-permeation chromatography (on Bio-Gel P-2). Fractions, compared with pure potassium salts, were bioassayed for effects on Amaranthus caudatus seedling growth in the dark for 4 days.
RESULTS: The LCSE robustly promoted amaranth hypocotyl elongation and inhibited root growth. The hypocotyl inhibitor was non-volatile, hot acid stable, hydrophilic and resistant to incineration, as expected for K+. The root inhibitor(s) had similar properties but were organic (activity lost on incineration). The root inhibitor(s) remained in the aqueous phase (at pH 2.0, 6.5 and 9.0) when partitioned against butan-1-ol or toluene, and were thus hydrophilic. Activity was diminished after electrophoresis, but the remaining root inhibitors were neutral. They became undetectable after paper chromatography; therefore, they probably comprised multiple compounds, which separated from each other, in part, during fractionation. On gel-permeation chromatography, the root inhibitor co-eluted with hexoses.
CONCLUSIONS: Cress-seed allelochemicals inhibiting root growth are different from the agent (K+) that over-stimulates hypocotyl elongation and the former probably comprise a mixture of small, non-volatile, hydrophilic, organic substances. Abundant components identified chromatographically and by electrophoresis in cress-seed exudate fitting this description include glucose, fructose, sucrose and galacturonic acid. However, none of these sugars co-chromatographed and co-electrophoresed with the root-inhibitory principle of LCSE, and none of them (in pure form at naturally occurring concentrations) inhibited root growth. We conclude that the root-inhibiting allelochemicals of cress-seed exudate remain unidentified.
摘要：
目的：水芹种子释放化感物质，过度刺激邻近（潜在竞争）下胚轴的伸长并抑制其根生长。下胚轴启动子是钾，但是根抑制剂身份不明；这里调查了它的性质。
方法：通过相分配将吸收的紫菜种子中的低分子量水芹种子渗出液（LCSE）进行分馏，纸色谱，高压电泳和凝胶渗透色谱（在Bio-GelP-2上）。分数,与纯钾盐相比，在黑暗中进行了4天的生物检测，以确定其对Amaranthuscaudatus幼苗生长的影响。
结果：LCSE能强烈促进a菜下胚轴伸长，抑制根系生长。下胚轴抑制剂是非挥发性的，热酸稳定，亲水性,和抗焚烧-正如预期的K+。根抑制剂具有相似的性质,但是是有机的(在焚烧时失去活性)。当与丁醇-1-醇或甲苯分配时，根抑制剂保留在水相中（pH2.0、6.5和9.0），因此是亲水的。电泳后活性减弱,但其余的根抑制剂是中性的。它们在纸层析后变得无法检测到；因此，它们可能包含多种化合物，在分馏过程中彼此部分分离。在凝胶渗透色谱上，根抑制剂与己糖共洗脱。
结论：抑制根生长的水芹种子化感物质与过度刺激下胚轴伸长的试剂（K）不同，可能包含一种小的混合物，非挥发性，亲水性,有机物质。在符合本描述的水芹种子渗出物中，通过色谱和电泳鉴定出丰富的成分包括葡萄糖，果糖,蔗糖和半乳糖醛酸。然而,这些糖都没有与LCSE的根抑制原理进行共色谱和共电泳，并且它们中没有一个（在天然存在的浓度下以纯形式）抑制根的生长。我们得出的结论是，水芹种子分泌物的抑制根的化感物质仍未被识别。
方法：通过相分配将吸收的紫菜种子中的低分子量水芹种子渗出液（LCSE）进行分馏，纸色谱，高压电泳和凝胶渗透色谱（在Bio-GelP-2上）。分数,与纯钾盐相比，在黑暗中进行了4天的生物检测，以确定其对Amaranthuscaudatus幼苗生长的影响。
结果：LCSE能强烈促进a菜下胚轴伸长，抑制根系生长。下胚轴抑制剂是非挥发性的，热酸稳定，亲水性,和抗焚烧-正如预期的K+。根抑制剂具有相似的性质,但是是有机的(在焚烧时失去活性)。当与丁醇-1-醇或甲苯分配时，根抑制剂保留在水相中（pH2.0、6.5和9.0），因此是亲水的。电泳后活性减弱,但其余的根抑制剂是中性的。它们在纸层析后变得无法检测到；因此，它们可能包含多种化合物，在分馏过程中彼此部分分离。在凝胶渗透色谱上，根抑制剂与己糖共洗脱。
结论：抑制根生长的水芹种子化感物质与过度刺激下胚轴伸长的试剂（K）不同，可能包含一种小的混合物，非挥发性，亲水性,有机物质。在符合本描述的水芹种子渗出物中，通过色谱和电泳鉴定出丰富的成分包括葡萄糖，果糖,蔗糖和半乳糖醛酸。然而,这些糖都没有与LCSE的根抑制原理进行共色谱和共电泳，并且它们中没有一个（在天然存在的浓度下以纯形式）抑制根的生长。我们得出的结论是，水芹种子分泌物的抑制根的化感物质仍未被识别。
