Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 2

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych:  morphological response
help Sortuj według:

help Ogranicz wyniki do:
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
The total soluble sugar content and antioxidant enzyme activities were studied for the first time during axillary shoot formation in Magnolia × ‘Spectrum’ in vitro in response to BAP (0.3 mg lˉ¹), different levels of gibberellic acid (GA3; 0.0, 0.1, 0.5, 1.0 mg lˉ¹), sucrose (20 and 30 g lˉ¹) and nitrogen salts (KNO3/NH4NO3; 100/100% and 75/50% relative to MS medium). Among various GA3 and sucrose/nitrogen salts ratios, the most effective axillary multiplication (5.9 shoots/explant) and leaf formation (25.7 leaves per multiplied clumps) were obtained after addition of GA3 at 0.1 mg lˉ¹ to a BAP medium containing 20 g lˉ¹ sucrose and reduced levels of nitrogen salts (75% KNO3 and 50% NH4NO3). The addition of GA3 to the BAP medium enhanced shoot formation by 36% and leaf formation by 27%. The highest shoot formation capacity of M. × ‘Spectrum’ in vitro coincided with enhanced levels of soluble sugar and peroxidase (POD) activity. Increasing GA3 concentration from 0.1 to 1.0 mg lˉ¹ in the above medium resulted in inhibition of shoot and leaf formation and a decrease in the soluble sugar content. The influence of GA3 on the activities of catalase (CAT) and POD depended on its concentration and the levels of sucrose and nitrogen salts in the medium. The highest increase in CAT and POD activities, that coincided with the enhanced shoot formation capacity of M. × ‘Spectrum’ in vitro, was observed after addition of GA3 to the medium containing high levels of sucrose and nitrogen salts.
Soil nutrient pattern can be a functional tool for grassland restoration. In order to promote the growth of a specific or group of expected plant species, it is necessary to measure the responses of different species to nutrient – rich patches and detect the differences among them. In this article, we measured aboveground biomass and morphological traits of six species as dry weight, length, surface area, specific root length and diameter of fine roots in response to nitrogen addition patches using ingrowth core method. The six species are Artemisia scoparia, Stipa bungeana, Artemisia sacrorum, Artemisia giraldii, Lespedeza dahurica and Astragalus melilotoides. All are the dominant species in different stages of secondary succession of loess hilly region, China. Twelve individuals of each species were selected to install ingrowth cores. Six of the individuals were used as treatment group, they were treated to install with four cores of no (addition’s control), low, medium and high levels of nitrogen additions. Another six of them were used as species’ control group, the four installed cores around them had no nitrogen addition. The results showed that: 1) After 105 days in situ, for all the six species, summed dry weight, length and surface area measured in the four cores of the treatment group were significantly greater than the corresponding values in species’ control group. In aboveground biomass, however, only A. scoparia in the treatment group had significantly outweighed that in the species’ control group. 2) Irrespective of nitrogen additions levels, significant differences of length, diameter and surface area existed among the six species, which implied that species had their intrinsic species specific morphological traits. 3) In dry weight, length and surface area, the responses of all the six species to nitrogen addition levels were positive, significantly more roots were grew into the cores with higher nitrogen additions; while in specific root length, the responses were negative. 4) Perhaps the six species had a special nitrogen requirement, as interaction effects of species and addition levels in surface area were found significant. 5) The foraging precision of the six species to nutrient-rich patches had positive but insignificant correlation with root system size; there existed a significant positive correlation between the precision and the sensitivity to the designed patchy habiats. 6) Among the six species, A. scoparia, A. sacrorum and S. bungeana have higher sensitivity and precision than L. dahurica and A. melilotoides in terms of foraging the nitrogen addition cores or patches. It seems that fast growing species that dominate in early successional stage, like A. scoparia and S. bungeana in our case, obtained more benefits from nutrient patchy habitat. We advised that, in infertile lands, fertiliser be applied in a patchy way to accelerate the restoration of old fields as early as possible once they were abandoned.
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.