Gibberelliny. As operates gibberellin

you are: Gibberelliny

By consideration gibberellina as well as auksina, we face the same problem: as it is possible to explain that very small to quantity of the given substance are capable to supervise numerous and various morfogeneti-cheskie the reactions including germination of seeds, division and a stretching of cages, a bookmark tsvetkov. Only one phenomenon has been analysed in detail - an induction of hydrolysis of starch in bezzarodyshevyh barley seeds.

We know now that the control of splitting of starch gibberellinom is reduced to regulation of formation and liberation of enzymes. Drawing gibberellina on bezzarodyshevye barley seeds leads to occurrence and allocation amilazy (fig. 9.26), and also other enzymes. Amilaza causes starch hydrolysis (in Latin amylum), containing in endosperme barley grains.

If to remove alejronovyj a layer it is possible to show that enzyme formation occurs in this fabric. Hence, alejron produces and allocates gidroliticheskie the enzymes splitting spare nutrients in endosperme. These alejronovye the cages which are ' cages-targets ', also react on gibberellin. The given system can be an example organospetsificheskoj for growth regulation as gibberellin - some kind of a key to spare nutrients - it is formed in a germ containing unique in a seed capable fabrics to growth.

How gibberellin causes display a-amilaznoj activity? First, it is obvious that enzyme represents not simply activated form of preliminary synthesised inactive spare fiber, and is formed anew of amino acids making it. It has been shown by addition mechenyh amino acids to grains of barley or alejronovym to layers, inkubirovannym with gibberellinom. As a result there was a radio-activity inclusion in fiber. This inclusion was prevented ingibitorami fiber synthesis, such, as tsiklogeksimid. In a scene of action gibberellina in the course of fiber synthesis specifies that fact that ingibitory DNA-dependent of synthesis RNK (for example, aktinomitsin D) interfere as well with synthesis amilazy. From here it is possible to conclude that gibberellin should participate in formation of molecules mrnk on DNA-matrix in quality derepressora the genes coding gidroliticheskie enzymes; it as though authorises for development of these enzymes.

Attempts to prove existence such specific mrnk encounter the difficulties connected with very small quantity formed mrnk and absence of methods, allowing to distinguish it from others mrnk. Last problem has been recently solved thanks to detection on one end of molecules mrnk chains adeninovyh the rests. As adenin incorporates hydrogen communications with uridinom, this property allows to separate mrnk by means of a column with connected poliuridinom which can join adenin. Information RNK sorbiruetsja a column whereas others RNK freely pass through it. Then, having replaced a solution in a column, it is possible eljuirovat and to define mrnk - This method has shown that approximately through 4 ch after addition gibberellina mechenye nukleozidy join in mrnk by means of kernels alejronovyh cages. It occurs some hours prior to occurrence ' amilazy. Besides, occurrence a-amilazy is braked at addition at early stages ingibitora korditsepina which as it is considered, specifically prevents synthesis end mrnk. The later its effect is added korditsepin, the less. If it to add approximately through 12 ch after drawing gibberellina any ingibirujushchego it will not render influence any more. Hence, induced gibberellinom synthesis mrnk for a-amilazy by this time should come to the end.

The Specific nature again synthesised mrnk has been finalised by means of a combination of graceful methods. After allocated mrnk have brought in fiber synthesising system in vitro, containing ribosomes, trnk, necessary enzymes and amino acids, by a combination immunohimicheskih and elektroforeticheskih methods it has been shown that the formed fiber is identical present a-amilaze

Approximately at the same time, when appears mrnk, the sharp increase in number by the policy and rough endoplazmaticheskogo retikuluma in alejronovyh cages is observed also. Such changes are typical for the cages making sekretiruemye enzymes. Really, gibberellin, apparently, promotes both secretions, and to synthesis of enzymes. It has been shown that gibberellin initiates formation not only a-amilazy, but also others a hydromanhole, especially proteazy and ribonukleazy. Thus, one hormone, obviously, causes a number of the events leading to fast transformation of all spare nutrients of a seed in substances, accessible to a young plant. Gibberellin promotes also to allocation of all these enzymes from alejronovyh cages in endosperm. Synthesis and liberation a-amilazy begins approximately through 9 ch after addition gibberellina (fig. 9.26). Ribonukleaza it is synthesised simultaneously with a-amilazoj, but before its allocation from cages should pass more than 24 ch from the moment of addition gibberellina. Enzymes split spare nutrients on soluble products which then transport to growing apeksam plants and are used as energy sources and the materials necessary for formation of new cages.

If gibberellin can derepressirovat certain genes in cages alejronovogo a layer, it is not surprising that it can influence also division and differentiation of cages in other parts of a plant by ' inclusions ' other genes. What genes thus join, almost for certain depends by nature cages. Not many works devoted to a role gibberellina in initsiatsii or the control of a stretching of cages are made. At absolutely adult plants of oats gibberellin is responsible for considerable lengthening mezhdouzly a stalk before flowering. It has been established that in absence auksina such lengthening is completely caused by a stretching of cages though naturally in the presence of certain quantity auksina in knot occurs as well cell fission. Initial results show that gibberellin induces a stretching of cages thanking podkisleniju cellular walls approximately in the same way as it has been described earlier for auksina. However sensitive to gibberellinu cages do not react on auksin. Distinctions between cages of these two types speak, possibly, presence at them different receptors of hormones.