Pores in cell walls allow movement of cell products between cells. These pores are filled with an extension of the endoplasmic reticulum, the membrane-like filaments within a cell. This extension called the plasmodesmata is essential to plants because of the cell walls. Animal cells do not have cell walls. These typically are large to move small molecules such a glucose but often need some energy dependent assistant to move larger ones such as proteins. It is hypothesized that when some corn varieties are chilled the movement of the compounds from the chloroplasts in the leaf cells to the bundle cells adjacent to the veins for the final production of glucose is inhibited (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2958785).
Larger molecules such as RNA and proteins also move via plasmodesmata between cells with some specific chaperones’ molecules assistance. This same type of assistance allows viruses to move between cells as well, eventually reaching the growing point to cause a systemic disease.
Movement of carbohydrates from leaves to growing points, roots and corn stalks is facilitated with the plasmodesmata between cells of the phloem. Hormones are also moved in the phloem to other plant parts by the same system. Root cells also have plasmodesmata for hormone attraction of carbohydrates and proteins for growth.
Plasmodesmata represent another unique feature of plants, hidden from most of us, that is affecting the performance of the corn hybrid each season in our fields.
About Corn Journal
The purpose of this blog is to share perspectives of the biology of corn, its seed and diseases in a mix of technical and not so technical terms with all who are interested in this major crop. With more technical references to any of the topics easily available on the web with a search of key words, the blog will rarely cite references but will attempt to be accurate. Comments are welcome but will be screened before publishing. Comments and questions directed to the author by emails are encouraged.