I often found dividing chloroplasts in the mesophyll cells in mature conifers needles under the electron microscope. I have understood from literature that chloroplast multiply by division in the meristem and expanding leaves. Could chloroplast division still take place also in mature leaves? (I think it would make sense to “renew” the organelles since conifers retain the needles for several years.) Has somebody been studying the chloroplast division in mature leaves?
Chloroplast divisions still occure in mature leaves also! Of course efficiency of division depend e.g. on the species and cells metabolism activities. Additionally other semi-auto organelles - mitochondria - also are able to divide in mature cells.
Best wishes!
Yes chloroplast division continues in older leaves in particular in plant species keeping leaves intact for years. Speed of metabolic processes/division in older leaves of such type of plants decreases with the time but still one can find activity.
Plastid biogenesis continues in mature leaves and this depends mainly on the species type and on the environmental factors sourrinding the plant as well as the plant age.
By all means the process continues and the biogenesis also dictates the rate of photosynthesis. The whole process is governed by the phytohormones as well. If you google scholar or pubmed for articles, you will find vast literature on the same.
As discussed above, chloroplast division can continue in mature leaves. From an experimental point of view, to complement your EM studies, you might check this in your particular case by looking at red autofluorescence (blue excitation) of chlorophyll with fluorescence (confocal would help but not be necessary) microscopy of living needles or needle slices. Assuming that there is not interfering autofluorescence from other molecular species, active chloroplast division- fission- should be quite apparent as the central constriction develops. You might be able to do time lapse fluorescence if your needles are not perturbed too much by separation from the plant. There are ways to keep leaves sections (I would think that needles would be even hardier) alive during examination (see Fitzgibbon et al. 2013 Plant Cell 25:57-70)
ya ithink , Chloroplast divisions fromyoung leaf till occure in mature leaves also! Of course efficiency of division depend e.g. on the species and cells metabolism activities. Additionally other semi-auto organelles - mitochondria - also are able to divide in mature cells. at the hydrilla sp
Hi, thanks for all, especially the hint for fluorescence microscopy.