EFFECT OF DROUGHT STRESS ON BENDING STIFFNESS IN PETIOLES OF CALADIUM BICOLOR (ARACEAE)
EFFECT OF DROUGHT STRESS ON BENDING STIFFNESS IN PETIOLES OF CALADIUM BICOLOR (ARACEAE)
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DOI：
10.3732/ajb.1300158
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发表时间：
2013-11-01
影响因子：
3
通讯作者：
Speck, Olga
中科院分区：
文献类型：
--
作者：
Caliaro, Marco;Schmich, Florian;Speck, Olga
研究前提：细胞膨压在草本植物的机械稳定性中起着重要作用。这项对双色花叶柄“Candyland”的研究分析了弯曲刚度和细胞膨胀之间的相关性。这些结果为了解潜在的形式-结构-功能关系以及机械性能对水可用性的依赖性提供了新的见解。方法：叶柄的弯曲模量E是通过两点弯曲试验计算的，并考虑了锥形模式。通过压力探针测试研究了萎蔫过程中薄壁细胞相应的膨压。主要结果：枯萎叶柄的 E 值显着低于供水充足的叶柄。当比较浇水良好的叶柄与薄壁组织膨压值在相同范围内的干旱胁迫的叶柄时，也发现了这些差异。这些结果表明还有一个对干旱胁迫敏感的机械系统。在分析不同叶柄组织对轴向面积二阶矩的贡献的基础上，并通过使用不同组织的实验测定值和文献值 E，我们能够（1）重新计算完整叶柄的 E 并将其与实验数据进行比较，以及（2）定量估计不同组织对叶柄弯曲刚度和 E 的重要性。结论：我们的结果表明，Caladium bicolor 'Candyland' 叶柄的弯曲刚度在生长期间有所下降。萎蔫的原因是（1）水分流失引起的厚角组织纤维机械效率下降和（2）薄壁组织细胞膨胀损失。
Premise of the study: Cell turgor plays an important role in the mechanical stability of herbaceous plants. This study on petioles of Caladium bicolor 'Candyland' analyzes the correlation between flexural rigidity and cell turgor. The results offer new insights into the underlying form-structure-function relationship and the dependency of mechanical properties from water availability.Methods: Bending modulus E of petioles is calculated from two-point bending tests, taking into account the tapering mode. The corresponding turgor of parenchyma cells during wilting is investigated by pressure probe tests.Key results: Wilting petioles show highly significant lower values of E than petioles with sufficient water supply. These differences are also found when comparing well-watered petioles to drought-stressed petioles having parenchyma turgor values in the same range. These results indicate an additional mechanical system sensitive to drought stress. On the basis of analyses of the contribution of different petiolar tissues toward the axial second moment of area and by using experimentally determined and literature values of E for the different tissues, we were able to (1) recalculate E of the intact petiole and to compare it with experimental data and (2) quantitatively estimate the importance of the different tissues for flexural rigidity and E of the petiole.Conclusions: Our results show that the decrease in flexural rigidity of petioles of Caladium bicolor 'Candyland' during wilting results from (1) a water-loss-induced decrease in mechanical efficiency of collenchyma fibers and (2) turgor loss of parenchyma cells.