Programa de Pós-Graduação em Biodiversidade Vegetal e Meio Ambiente, Instituto de Botânica, São Paulo, Brazil; Núcleo de Pesquisa em Plantas Ornamentais, Instituto de Botânica, Caixa Postal 68041, São Paulo 04045-972, SP, Brazil.
Plant Physiol Biochem. 2013 Oct;71:144-54. doi: 10.1016/j.plaphy.2013.07.005. Epub 2013 Jul 19.
Nidularium minutum is a tropical bromeliad that grows in natural environment with temperatures ranging from 2 to 30 °C. In the present work we cultivated this species in vitro at 5, 10, 15, and 25 °C for 3 and 6 months aiming at assessing biochemical and morphological responses that allow its survival under low temperatures. No survival was observed for plants cultured constantly at 5 °C and the lowest biometric parameters were found for those grown at 10 °C. A thick aquiferous parenchyma, accumulation of reducing sugars, and increased pectin content in the cell walls were observed in plants grown at 10 and 15 °C when compared to those maintained at 25 °C. In plants cultured at 10 °C, leaf bleaching correlated with low chlorophyll content and lower survival rate after 6 months when compared to those grown at 15 °C. The best in vitro culture condition for slow growth and plant acclimatization was found to be at 15 °C. This probably correlated with the immediate availability of carbon to restore growth during acclimatization and also with higher root initiation under this condition. This study brings information about the responses related to functional adaptation to low temperatures in N. minutum cultured in vitro that can also be implicated in its survival under natural conditions. Additionally, it suggests the best temperature to form a minimal growth collection to be used in restocking and conservation programs for endangered tropical bromeliads.
微小鸟巢凤梨是一种生长在温度范围为 2 至 30°C 的自然环境中的热带凤梨科植物。在本研究中，我们将该物种在 5、10、15 和 25°C 下分别培养 3 和 6 个月，以评估其在低温下生存的生化和形态响应。在 5°C 下培养的植物无法存活，而在 10°C 下生长的植物的最低生物计量参数最低。与在 25°C 下生长的植物相比，在 10 和 15°C 下生长的植物的薄壁组织含水量增加、还原糖积累和细胞壁中果胶含量增加。在 10°C 下培养的植物，叶片白化与叶绿素含量降低以及 6 个月后存活率较低有关，而在 15°C 下生长的植物则没有这种现象。在低温下缓慢生长和植物驯化的最佳体外培养条件被发现是在 15°C。这可能与在驯化过程中立即获得碳以恢复生长有关，也可能与在这种条件下根系起始更高有关。本研究提供了有关在体外培养的微小鸟巢凤梨适应低温的功能的信息，这也可能与其在自然条件下的生存有关。此外，它还建议了形成最小生长集合的最佳温度，以用于补充和保护濒危热带凤梨科植物的计划。
