Changes in Wall Polysaccharides of Squash (Cucurbita maxima Duch.) Hypocotyls under Water Stress Condition I. Wall Sugar Composition and Growth as Affected by Water Stress
Changes in Wall Polysaccharides of Squash (Cucurbita maxima Duch.) Hypocotyls under Water Stress Condition I. Wall Sugar Composition and Growth as Affected by Water Stress
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水分胁迫条件下南瓜下胚轴壁多糖的变化一、水分胁迫对壁糖组成及生长的影响
DOI：
10.1093/oxfordjournals.pcp.a077385
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发表时间：
1987
影响因子：
4.9
通讯作者：
S. Kuraishi
中科院分区：
文献类型：
--
作者：
N. Sakurai;S. Tanaka;S. Kuraishi
暗生南瓜（Cucurbita maximaDuch.）通过向水培溶液中添加60mM聚乙二醇（PEG）（水分胁迫），幼苗的生长显著减少。在非胁迫条件下，随着下胚轴的生长，半纤维素和纤维素的含量增加，但水分胁迫显著降低了这些含量。水分胁迫解除后，壁多糖含量的增加又恢复。每下胚轴的纤维素和果胶中糖醛酸的量的变化与生长平行（r=0.95和0.98，分别）。半纤维素中大部分糖组分的含量也随着下胚轴的生长而变化。未胁迫下胚轴的果胶和半纤维素半乳糖含量在第2天下胚轴以最大生长速率生长时增加，然后下降。结果表明，水分胁迫在抑制下胚轴生长的同时，显著降低了下胚轴细胞壁中大部分多糖的净增加量，但不影响果胶和半纤维素B中部分半乳糖多糖的合成。我们假设，非半乳糖壁多糖的合成与下胚轴的生长和含半乳糖的多糖的合成与保存的潜力的细胞壁被松开，因为下胚轴生长迅速和完全恢复时，水胁迫被解除。
Hypocotyl growth of dark-grown squash (Cucurbita maximaDuch.) seedlings was greatly reduced by the addition of 60 mM polyethylene glycol (PEG) to hydroponic solution (water stress). When PEG was removed after one day, growth promptly recovered.The contents of hemicelluloses and cellulose in the wall increased under unstressed condition as hypocotyls grew but these increases were substantially reduced by water stress. The increases in wall polysaccharide contents recovered when the water stress was relieved. The amounts per hypocotyl of cellulose and that of uronic acid in pectin changed in parallel with the growth (r=0.95 and 0.98, respectively). The amounts of most of the sugar components of hemicelluloses also changed in parallel with hypocotyl growth. Pectic and hemicellulosic galactose content of unstressed hypocotyls increased to day 2 when the hypocotyl grew at a maximum growth rate, then decreased. In contrast, galactose content of stressed hypocotyls progressively increased to the end of the experiment.The results indicated that water stress substantially reduced net increases in most of the polysaccharides of the hypocotyl cell walls when it reduced the growth, but it did not affect syntheses of some galactosic polysaccharides in pectin and hemicellulose B. We assume that the syntheses of non-galactosic wall polysaccharides are associated with hypocotyl growth and the synthesis of galactose-containing polysaccharides with preservation of the potential of the cell wall to be loosened, since hypocotyl growth promptly and completely recovers when water stress is relieved.