Fast movements of plants. A twisting of short moustaches

you are: Fast movements of plants

Some plants which do not have a rigid stalk, are capable to support themselves and to grow above the next kinds by means of thin bichevidnyh the appendages named short moustaches. These bodies - usually modified parts of a stalk or leaves - at the growth make circular motions that increases probability of contact to a potential support. Having met suitable object, they change speed and a growth direction so that to be hooked for it and to tighten a plant upwards.

At some plants short moustaches are twisted round a support whereas at others they form the sticky small pillows growing into cracks on supporting surfaces (fig. 13.7). At kinds with curling short moustaches apikalnaja the short moustache part forms a ring round basic object. Soon after that more bazalnaja the part forms a free ring in space, tightening thereby a plant is closer to a support. Free rings can odrevesnevat that raises their breaking strength. The twirled short moustache strastotsveta Passiflora coerulea, forming both contact, and free rings, can develop the effort equal 350-750 g that corresponds to weight of several foots of a stalk of this liana.

Short moustaches can be tigmonasticheskimi (the twisting direction is predetermined by asymmetry in short moustache structure) or tigmotropicheskimi (the direction depends on a direction of irritations). Short moustaches of that and other type, started to twist, are usually straightened, if the contact stimulus is prematurely removed. Therefore short-term contact with an animal, a branch shaking from a wind or other mobile object usually does not conduct to long change in orientation of short moustaches.

The Twisting is activated by light, but unlike stimulation of movements of leaves at niktinasticheskih plants phytochrome here, apparently, does not participate. Light action, possibly, is directly connected with requirement in ATF, formed at photosynthesis as it is partially possible to replace light with addition ATF to the incubatory environment on which short moustaches float. During a twisting formation of considerable quantities ADP and P1 as a result of hydrolysis ATR is noted.

As Favourite experimental object for studying of a twisting of short moustaches peas (Pisum sativum) serve. Reaction at it tigmonasticheskaja, and it is possible to stimulate it, stroking bottom (abaksialnuju) the party of a short moustache a glass stick. The twisting which begins in two minutes (fig. 13.8) and proceeds more than 48 hours, consists of two various phases: in the beginning abaksialnye cages are compressed, and top (adaksialnye) are stretched; after that cages on both parties are stretched, and adaksialnye faster, than abaksialnye.

Apparently, in regulation of change of size of the cages, leading to a twisting, two hormones - auksin and etilen participate. The cut off short moustaches of peas and other studied plants at processing auksinom twist in rings without tactile stimulation (fig. 13.9); it is not surprising, as auksin stimulates growth, and formation of rings is connected with the big increase in speed of a stretching of cages.

However it depends on asymmetric growth abaksialnyh and adaksialnyh cages, and meanwhile occurs even in reply to symmetric processing auksinom. Therefore adaksialnye and abaksialnye cages should react on auksin differently. Partially it can depend on a hormone etilena. Auksin stimulates in short moustaches, as well as in many other vegetative fabrics, synthesis etilena (see gl. 10), and such synthesis in abaksialnyh short moustache cages occurs, probably, several times faster, than in adaksialnyh. Etilen does membranes nontight, and quantity increase etilena in abaksialnyh cages is accompanied by leak of the dissolved substances from vakuoli that conducts to compression of these cages in an early phase of a twisting. Therefore distinctions in the maintenance etilena in abaksialnyh and adaksialnyh cages allow to explain and a difference in their stretching during the second phase.

The short moustache Top is most sensitive to tactile stimulation, but such stimulation induces to curl as a top, and bazalnye zones; it specifies that any factor extends on a fabric. Recollect that auksin moves on plant fabrics in bazipetalnom a direction. Nevertheless auksin cannot be the primary transmitter as the stimulus is transferred much faster, than auksin. Probably, auksina any other event probably connected with movement of ions should precede action. We yet do not know, whether there are in short moustaches the excitable cages, capable to transfer action potential as at a mimosa and some insectivorous plants, or any other form of an electric signal here participates.