Auxins- phototropism

[Guest]

these are links to wikipedia : they talk about the role of auxins, and phototropism.

-auxins are vegetal hormones that can be found in various bio plant boosters.

- phototropism : if only a part of the plant receives light, then the auxins move to the shaded branches , makes them grow so they reach the light.

giberrelin

giberrelin is produced by plants, it's a hormone.It seems that giberrelic is produced by the plant, therefore inducing male flowers, when it is stressed.
A theory says one could inhibit the effect of stress on the plant by manipulating its stress or shock hormones, supposedly .

interesting for us all I think



auxins

phototropism

 

[Space Ghost]

im pretty sure that MJ is gravitrophic, not phototrophic.

 

[Guest]

Marijuana(and almost all plant matter) is gravitropic, autotropic and phototropic...smart guy

 

[socker1314]

giberellin is the shit though, used to use it back in the day in high school in the greenhouse. giberellin will get you HUGE stems and stalks, lol.

 

[Guest]

I have the impression giberrellin promotes abnormal growth.

 

[Guest]

I have noticed something :

I have a female mother , 100% female.I topped her, but did not make a clean cut, some piece of leaf/stem was torn but stayed on the plant : it produced a male flower.It happened already on another mother.
Those are 100% female, I never saw any male flower on them.BUT...when I do that dirty topping, they produce male flowers where the cut was made.

We know that Male flowers are forced by giberellin...therefore I think that my messy cut gave the branch some stress, that induced giberellin production (or movement), that itself produced a male flower.


Now I wonder if there is an hormone that is the opposite of giberellin, we could either use it to force a plant into being female, as well as for eliminating consequences from various stresses.

I also wonder if giberellin is the phyto equivalent to testosterone for humans, inducing male caracteristics on female indiduals....there should be a corresponding female hormone then

Am I being relevant here.....mmmmm ?

 

[Guest]

from hamburg univeristy :"In 1926 studied the Japanese E. KUROSAWA a rice disease that is known as the ‘foolish seedling’-disease in Japan. The plants grow extremely fast, look spindly and pale and break off easily. KUROSAWA detected that the reason for this abnormal growth is a substance that is secreted by a parasitic fungi (Fusarium moniliforme = Gibberella fujikuroi). It was termed gibberellin.

During the thirties was gibberellin isolated and crystallized by Japanese scientists from Tokyo (YABUTA and SUMIKI ), though it was almost forgotten in the following years. In 1956 isolated C. A. WEST and B. O. PHINNEY a gibberellin from Phaseolus vulgaris and other plants, thus showing that these compounds are far-spread in the plant kingdom. Today are more than 110 different gibberellins known (GA1, GA2,....GA3, GA4.....GA110) that differ only little chemically but very much in their biological activities.

Roughly 30 percent of all known gibberellins are biologically active. All higher plants contain presumably at least one, but usually several active and inactive gibberellins that exist in different concentrations depending on the respective tissue.

Gibberellins are diterpenoids derived from four isoprenoid units forming a system of four rings. It is distinguished between gibberellins of 19 and such of 20 C-atoms. The twentieth C-atom is not part of the four rings but belongs to a side chain (CH3 in GA12, CH2OH in GA15, CHO in GA19 or COOH in GA28). Both enumeration and the illustration below show, how the single structures differ.



Young, growing meristematic cauline tissue, apical root cells, young fruits, as well as unripe or germinating seeds are all rich in gibberellins. In sun flowers is the gibberellin content highest in the young leaves and in the uppermost internodes while it decreases continuously towards the basal leaves and internodes.

Gibberellin content and growth velocity of a tissue are correlated. Despite the shoot are high concentrations measured, too, in the root tips. The idea that they are produced in the roots seemed logical though indications exist that they are only converted in the roots, i.e. that one gibberellin is transported from the shoot into the root where it is converted another one. The new product is then transported back via the xylem into the shoot. Both in xylem- and phloem exuded matter have gibberellins been detected showing how the distribution mechanism for hormones works in this type of plant. Moreover exist reliable indications that symplastic transport exists in the tissues themselves.


Biological activities. Especially impressive is the demonstration of the gibberellin GA3 onto mutants of Phaseolus vulgaris characterized by dwarfism due to a genetic defect. After treatment with gibberellins develop plants of the same size as the control plants (without genetic defects; PHINNEY; 1956). The result points to a defect in the synthesis of GA3 as the cause of dwarfism. Similar results have been obtained with dwarfism mutants of other cultured species. Gibberellins promote especially elongation and not growth by cell division. They stimulate the germination of pollen and the growth of pollen tubes. They induce the development of parthenocarpous fruits like apples, pumpkin, and egg-plants twice the size of normal fruit.

In a number of plant species is flower formation controlled by extern factors, especially by light (short-day plants and long-day plants) or low temperatures (vernalization). If certain long-day plants or plants requiring vernalization (Hyoscyamus, Daucus, Crepis, Silene) are cultivated under short-day conditions and/or without a cold stimulus, flower formation does not take place. After addition of GA3, though, do they flower even without the otherwise necessary extern signals. This does not mean that gibberellins take actively part in flower formation. It seems more as if flower formation in the mentioned species were dependent on a previous elongation of the stem axis, and that gibberellins stimulate mainly this step. In most other long-day plants (whose stem axis does not elongate immediately before flower formation) and in all short-day plants display gibberellins no effect on flower formation. In plants germinating only in light was it shown that gibberellins are also able to substitute PFR. Gibberellins (like the best-studied GA3) control the formation and secretion of hydrolases in grains (like that of barley): the mobilization of endosperm storage compounds during germination supplies the embryo with nutriments. A number of hydrolases, among them the alpha-amylase, a protease, and a ribonuclease participate in this process. They are produced in the cells of the aleuron layer during the early stages of embryo germination . The way in which this reaction works was elucidated in the laboratory of J. E. VARNER at the Washington University in St. Louis at the beginning of the seventies.

Under the influence of GA3 rises the concentration of active alpha-amylase as a consequence of enhanced alpha-amylase production. Alpha-amylase is uncomplicated to detect and is therefore a suitable marker for the hormone-controlled enzyme production of this system. The production is inhibited by transcription inhibitors (like actinomycin D or chlororamphenicol). Simultaneous to the enzyme synthesis increases the endoplasmatic reticulum in size and new polysomes are produced. Involved is an increased incorporation of phospholipids in membranes as well as the synthesis of enzymes required for the formation of new membranes

The results indicate that GA3 stimulates at first the production of a protein synthesis machinery that produces in a second step the mentioned hydrolases. Here, too, has GA3 a selective effect since an enforced production of alpha-amylase mRNA was detected after the application of GA3.

It should be mentioned though that the activities observed in barley seedlings could be reproduced only with few species though the differentiation steps were the same. It has therefore been asked whether the change in the concentration of GA3 is not just a side effect of the normal process of differentiation (P. HALMER; 1985)."

 

[guineapig]

Yes gibberellins can induce maleness so it is advisable to use synthetic giberellins
during the veg period......however natural kelp extracts containing low levels of
naturally occurring gibberellins should be all-around fine......

On a 100% female (really, is there such a thing?), stress can induce male flowers so it
looks like when you snipped the plant reacted by forming a male flower....

There is a Dutch Masters product called "Reverse" which causes male plants to turn
female.....you add this product once right when you flip into 12/12.....i'm not 100%
sure what is in this product.....

Plant hormonal interactions are much more complex than Animal hormonal interactions.
We know so much more about the molecular mechanics of animals than plants....

kind regards from guineapig

 

[Guest]

thx for your reply, this interest me a lot

 

[outhereinthesun]

This should be the most interesting thread on here,

Peace

 

[photoperiodic]

as I understand the use of gibberellins cause mutations once upon a time people used them by soaking seed with witch hazel. then growing them out a very strong poisonous cocktail.the plants reactions were severely mutated.