Rosa Mariana, Hilal Mirna, González Juan A, Prado Fernando E
Cátedra de Fisiología Vegetal, Facultad de Ciencias Naturales e IML, Miguel Lillo 205, CP 4000, San Miguel de Tucumán, Argentina.
Plant Physiol Biochem. 2009 Apr;47(4):300-7. doi: 10.1016/j.plaphy.2008.12.001. Epub 2008 Dec 16.
The effect of low temperature on growth, sucrose-starch partitioning and related enzymes in salt-stressed and salt-acclimated cotyledons of quinoa (Chenopodium quinoa Willd.) was studied. The growth of cotyledons and growing axes in seedlings grown at 25/20 degrees C (light/dark) and shifted to 5/5 degrees C was lower than in those only growing at 25/20 degrees C (unstressed). However, there were no significant differences between low-temperature control and salt-treated seedlings. The higher activities of sucrose phosphate synthase (SPS, EC 2.4.1.14) and soluble acid invertase (acid INV, EC 3.2.1.25) were observed in salt-stressed cotyledons; however, the highest acid INV activity was observed in unstressed cotyledons. ADP-glucose pyrophosphorylase (ADP-GPPase, EC 2.7.7.27) was higher in unstressed cotyledons than in stressed ones. However, between 0 and 4days the highest value was observed in salt-stressed cotyledons. The lowest value of ADP-GPPase was observed in salt-acclimated cotyledons. Low temperature also affected sucrose synthase (SuSy, EC 2.4.1.13) activity in salt-treated cotyledons. Sucrose and glucose were higher in salt-stressed cotyledons, but fructose was essentially higher in low-temperature control. Starch was higher in low-temperature control; however, the highest content was observed at 0day in salt-acclimated cotyledons. Results demonstrated that low temperature induces different responses on sucrose-starch partitioning in salt-stressed and salt-acclimated cotyledons. Data also suggest that in salt-treated cotyledons source-sink relations (SSR) are changed in order to supply soluble sugars and proline for the osmotic adjustment. Relationships between starch formation and SuSy activity are also discussed.
研究了低温对藜麦（Chenopodium quinoa Willd.）盐胁迫和盐适应子叶生长、蔗糖 - 淀粉分配及相关酶的影响。在25/20℃（光照/黑暗）下生长并转移至5/5℃的幼苗子叶和生长轴的生长低于仅在25/20℃（非胁迫）下生长的幼苗。然而，低温对照和盐处理幼苗之间没有显著差异。在盐胁迫子叶中观察到较高的蔗糖磷酸合酶（SPS，EC 2.4.1.14）和可溶性酸性转化酶（酸性INV，EC 3.2.1.25）活性；然而，在非胁迫子叶中观察到最高的酸性INV活性。非胁迫子叶中的ADP - 葡萄糖焦磷酸化酶（ADP - GPPase，EC 2.7.7.27）高于胁迫子叶。然而，在0至4天期间，盐胁迫子叶中观察到最高值。盐适应子叶中观察到ADP - GPPase的最低值。低温也影响盐处理子叶中的蔗糖合酶（SuSy，EC 2.4.1.13）活性。盐胁迫子叶中的蔗糖和葡萄糖含量较高，但果糖在低温对照中基本较高。低温对照中的淀粉含量较高；然而，在盐适应子叶中0天时观察到最高含量。结果表明，低温对盐胁迫和盐适应子叶中的蔗糖 - 淀粉分配诱导了不同的反应。数据还表明，在盐处理的子叶中，源 - 库关系（SSR）发生了变化，以便为渗透调节提供可溶性糖和脯氨酸。还讨论了淀粉形成与SuSy活性之间的关系。
