Which metabolic mechanisms are adopted by plants and why?
fruits, leaves and stems exposed to light manifested intensive color. If we cultivate the same cultivar in wall shadow, plants shadow or under sunlight, we find morphological, anatomical and physical variations in tissues constitutes the plant of varing raised plants of the same cultivar. Thanks indeed
- Strong wind and coldness causes stunting in plants
- Plants increase solids in cells (salts etc) to reduce crystal building in cells
- relocation of water outside cells (between cells so that crystallisation is not harming the plant
There are many limitations to talk about why plants in the alpine are not luxuriously growing - much of the primary productivity is invested to resist the prevailing stress conditons: the low temperature is also a cause for the limiting concentration of available nitrogen, besides the lower density of organisms/organic material/ availability, soils are vulnerable to leaching and are deprived of other mobile elements, and have lower pH, the ecosystem is also not stable (winter/summer, scree is also common) and disturbance tolerants including annuals are commenly dominating, density of air which includes oxygen is also limiting....
In additions, UV rays also play role in stunting of plants in high altitude.
I recently visited a Andean site (paramo) in Ecuador at 3800m and observed many species with rosette growth forms. UV, temperature, and wind were mentioned as possible evolutionary drivers. Can anyone explain the mechanism driving these trends? For example, hormones that promote stem elongation are less active at colder temperatures? Or secondary compounds that act to protect the cells from Uv rays?
Dear Georgianne W. Moore Esq.
1. Under high light intensities, dominated by shorter light waves not only Uv, plants urge its Acquired Systematic Resistance through the following.
1. in creasing growth retardants, ABA, Phaseic acid, Coumarins, dihydrophasieic acid and other phenol dervatives.
2. ABA and other retardants block the GAs synthesis and prevent the conversion of ent-7- cumaric acid to GA12 where all GAs derivatives are synthesized.
3. Shortages of GA3 inhibits the intercalary meristem growth resulted inshortest internodes, and thus leaves being close to each others to shade one another in order to mitigate the short wave adversity.
4. Shortages of GA and Auxins also inhibits the growth rate of leaves resulted in smaller leaf area on the expanse of thickness, where larger leaf area of low light intensities is usually accompanied with low thickness. This is obvious in high plant populations.
5. Plants shortages of Auxins shift the plants to substitute its low growth rate by branching releasing the apical dominance Auxins/CK ratio. Therefore, in field plant of low populations branches more to engage the lag of coverage percentage of soil
6. Prevail of of phenol derivatives such as anthocyanins pigments accumulated in epidermis and hypodermis to protects the internal tissues to prevent oxidant generations caused by hitting the cell molecules by short waves, particularly cellular membranes. Therefore, any fruits oriented to sun light possesses red color and test sweeter owing to the accumulation of pigments and osmotic solute as defense system.
Willkommen Sie
Very helpful, thank you Caser. I also found a recent study about the genetic and biochemical basis of UV protection in plants that was recently published in Science:
http://www.sciencemag.org/content/early/2012/02/08/science.1218091
Besides the aforementioned secondary metabolites, hormones and wind/light/etc. stress, I'd just like to point out that a major force is probably also primary metabolites or a lack thereof. The growing season in an alpine setting is invariably shorter compared to a lower elevation, snow-cover may occur etc. In that sense, and considering also the allocation of primary products into defense mechanisms, alpine plants simply have more limited possibilities for resource accumulation. Not sure where this conversation was heading, but I think it was important to point out anyways. Of course, there probably are adaptations to maximize photosynthate-utilization, be it in the thylakoids, resource allocation or where ever, but the main point is that to a certain extent dwarfism is a result of a lack of resources and a lack of time to accumulate them. But of course having a rosette form or another kind of short stature also minimizes evaporative losses, and is in itself useful (again to maximize resource-use efficiency).
Thanks Dear
Anke weisheit
Yemene G. Egziiabher W. Gerima
Babu Ram Pandey
Georgianne W. Moore
Anti Tenakane
Thanks for your kind participation in answering my questions, you were really helpful
indeed.
Stunting is an adaptation to adverse climatic condition. There may be factors related to soil fertility and any deficiencies.
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