logikblok-science:Plants Growth & Development - Upwards & Downwards The gifs above visualise
logikblok-science:Plants Growth & Development - Upwards & Downwards The gifs above visualise plants in early stages of development. To be successful plants need to grow upwards to capture as much sunlight as possible whilst also growing downwards to collect nutrients and water. This presents a unique set of developmental challenges which are controlled by specific hormones. Traditionally five major classes of plant hormones are identified: auxins, cytokinins, gibberellins, abscisic acid and ethylene.Auxin - Primarily manufactured in the tips of roots and shoots. It is transported from cell to cell through the parenchyma. Auxins presence in cells can influence cell elongation, cell division and the formation of adventitious roots.Gibberillins -These are especially abundant in seeds and young shoots where they control stem elongation by stimulating both cell division and elongation. Gibberellins are carried by the xylem and phloem.Cytokinins - Are found in sites of active cell division. They are transported in the xylem and work in antagonism with auxin to promote cell division. The different cytokinin to auxin ratios changes the outcome of the organ eg turning into a leaf or root, or stem etc.Abscisic acid - This is synthesized inside plastids (where plants store their pigments such as chloroplasts) it then diffuses out of the cells. Its main effect stops cell growth. It is also used in the closing of stomata in response to water stress.Ethylene - is actually a hydrocarbon and is present in most plant tissues. It can diffuse from within the plant and into the air and affects surrounding plants as well when wounded. Its main effect is in stress response and ripening.How we should see plants is as a highly interactive network of perception, control and feedback as a result of these hormones keeping the plant in balance. Previous posts on plant roots here, plant time keeping here and plant cells here.Source videos from the public lab kickstarter.awwwwwwwwwwwwwwwwwwwwwwww -- source link