Agriculture Reference
In-Depth Information
anatomical, and morphological signs and properties of the earlier life period of a plant
can be less seen, instead others can appear [8, 12]. Young seedlings differ from adult
trees in size, leaf form, and edge serration. Young seedlings of various breeds have
thorns, which are not observed on adult trees grown from these seedlings. There are
also distinctions, which concern morphology and a deviation angle of laterals from a
stem, productive morphogenesis, etc. In addition to the above-mentioned and many
other differences, young seedlings are mostly be characterized by better regenerative-
morphogenetic potentials than adult and older trees [12].
Completion of a juvenile phase of ontogenesis is usually associated with the devel-
opment of fl oral buds, but a lower part of a young tree crown may remain in a juvenile
stage, whereas fl owers are formed in its upper part and a young tree enters an adult
phase with an ability of fruiting [12].
The ideas of interrelationship between individual and historic development of liv-
ing organisms appeared back in the XIX century, when, according to A.A. Zhuchenko,
basic provisions of bio-genetic law of Friedrich Müller (1864) and Ernst Haeckel
(1866) were proclaimed. According to this law, ontogenesis recapitulates major phy-
logenesis stages of a group, which an individual organism belongs to Zhuchenko, A.A.
[13]. It is possible to regenerate roots from green cuttings of various woody plants
such as coniferous, oak; most of the fruit trees and others belong to hard-rooting spe-
cies, if grafting of 1- to 3-year-old seedlings is done. Most of the researchers believe
that advantages in regeneration ability of green cuttings taken from young seedlings
can be explained by the factor of juvenility; therefore, a seedling (in compliance with
a bio-genetic law) did not totally lose the properties of ancestral forms to regenerate
roots from stem parts [8, 9, 14, 15]. There is evidence that the plants, which were
described in old topics as those capable of adventive root formation, became hard-
rooted after many years [8, 9]. At present, physiological stress called trauma/damage
is considered to be an inductor of adaptive response of an organism, which facilitates
regeneration [8, 16].
15.2 MATERIALS AND METHODOLOGY
Post-trauma regeneration processes in perennial woody plants and their dependence
on meteorological factors were estimated according to the ability of some representa-
tives (species and intraspecific taxons) of
Pyrus
L.
to nonmorphogenetic post-trauma
regeneration. Pear cultivars Bere Desiatova, Umans'ka iuvileina, Kniahynia Ol'ha and
Sofiia, few rootstocks, and also cultivars of basic species
Pyrus communis
L., and
several other wild relatives of pears were studied.
Pear cultivars and species studied were grown in the collections of the National
dendrological park “Sofi yivka” of NAS of Ukraine, situated in the Central-Dnieper
elevated region of Podilsko-Prydniprovsk area of the Forest-Steppe Zone of Ukraine.
The area is characterized by temperate-continental climate with unstable humidifi -
cation and considerable temperature fl uctuations. Average many-year amount of
precipitation per year is 633.0 mm, its amount being 300-310 mm at +10
°
С, which
corresponds to the precipitation amount in dry southern areas of Ukraine. Average
many-year air temperature is +7.4
°
С.
Search WWH ::
Custom Search