Pollen tube are tolerant and even pollen damaged by X-rays and gamma rays can still grow pollen tubes. The interaction between the stigma-style and the pollen grain is a vital piece that contributes to the growth. The elongation of the tube is achieved with elongation of the cytoskeleton and it extends from the tip, which is regulated by high levels of calcium in the cytosol. The calcium levels help the synaptic vesicles in the membranes grow and extend at the tip. Polypeptides found in the style also regulate growth of tube and specific peptides that play a role in signaling for growth
Gum (botany) Gum (botany) Gum is a sap or other resinous material associated with certain species of the plant kingdom. This material is often polysaccharide-based and is most frequently associated with woody plants, particularly under the bark or as a seed coating. The polysaccharide material is typically of high molecular weight and most often highly hydrophilic or hydrocolloidal. Many gums occur as seed coatings for plant species; the adaptive purpose of some of these gummy coatings is to delay germination of certain flora seeds. An example of such a gummy coating occurs in the case of Western poison oak, a widespread shrub