Measurement of porosity in very small samples of plant tissue
Measurement of porosity in very small samples of plant tissue
复制标题
测量非常小的植物组织样品的孔隙率
作者：
E. Visser;G. Bögemann
植物芽和根的内部气体空间的相对体积（即孔隙率）在很大程度上决定了其对水淹的抵抗力，因为氧气可以通过这些空腔从植物的非水淹部分扩散到水下组织中。目前测量孔隙率的技术要么需要相对大量的植物组织（每个样品 200 毫克），要么耗时且对于特定类型的植物材料不够准确。这些限制是开发一种新的孔隙率测量方法的原因。从新鲜收获的植物中取出小段根，放入两片式硬明胶胶囊中，并在微量天平上称重。随后在真空下用水浸润根段，小心地吸干并再次称重。利用来自较大根部样本的重量增加和渗透组织的比重，可以计算出长度为 5 毫米、小至 3-5 毫克的单个根段的孔隙率。新方法将小样本的使用与高精度结合起来，并被证明对多种植物物种有用。用这种方法获得的孔隙率数据将提高我们对小规模过程的了解，例如根尖的通气组织发育。
The relative volume of internal gas spaces (i.e., porosity) of the shoot and roots of a plant largely determines its resistance to flooding, as oxygen may diffuse through these cavities from non-flooded parts of the plant into the submerged tissues. The current techniques to measure porosity either need relatively large amounts of plant tissue (200 mg per sample), or are time-consuming and not sufficiently accurate for specific types of plant material. These limitations were the reason to develop a new method of porosity measurement. Small segments of roots were taken from freshly harvested plants, placed in a two-piece hard gelatin capsule and weighed on a microbalance. The root segments were subsequently infiltrated with water under vacuum, blotted carefully and weighed again. Using the increase in weight and the specific weight of infiltrated tissue, derived from a larger sample of roots, it was possible to calculate the porosity of individual root segments as small as 3–5 mg with a length of 5 mm. The new method combines this use of small samples with a high accuracy, and proved useful for a variety of plant species. Porosity data obtained with this method will improve our knowledge of small-scale processes such as aerenchyma development in root tips.