Magnólia Martins Alves

Initial growth in seedlings of Adenanthera pavonina L. for different substrates

Adenanthera pavonina L., a species that produces great quantities of viable seeds, is widely used in the reclamation of degraded areas. The aim was to study the effect of different substrates on the emergence and initial growth of seedlings of A. pavonina. The experiment was carried out at the Centre for Agrarian Science of the Federal University of Paraiba, in Areia, Pariba, Brazil. The experimental design was completely randomised (CRD) with the treatments composed of 14 substrates: sand, compost, fine vermiculite, sawdust, carbonised rice hull, sand + compost in a 1:1 ratio, sand + sawdust in a 1:1 ratio, sand + cured cattle manure in a 1:1 ratio, compost + sawdust in a 1:1 ratio, compost + cattle manure in a 1:1 ratio, fine vermiculite and sand in a 1:1 ratio, fine vermiculite + sawdust in a 1:1 ratio, fine vermiculite + compost in a 1:1 ratio, and fine vermiculite + cured cattle manure in a 1:1 ratio, in four replications of 25 seeds. The following were evaluated: emergence, first count, speed of emergence index, and length and dry weight of the roots and shoots. Given the results, it was found that the sand, compost and fine vermiculite substrates, as well as the mixtures of sand + compost, compost + sawdust and fine vermiculite + sawdust in a 1:1 ratio are the most efficient for promoting the emergence and initial growth of seedlings of A. pavonina.

Potencial fisiológico de sementes de Clitoria fairchildiana R. A. Howard. - Fabaceae submetidas a diferentes regimes de luz e temperatura

Clitoria fairchildiana Howard, a native of the Amazon region is widely used in reforestation programs, planting trees in the streets, public squares, roads and parking lots because of its broad and leafy canopy and its rapid growth. Thus, the objective was to study the influence of light and temperature regimes on germination and vigor of C. fairchildiana seeds. We evaluated the physiological potential of seeds under constant temperatures (25 and 30°C) and alternating (20-30°C) in different light regimes: white, green, far-red, red and darkness. The experimental design was completely randomized in a factorial 3x5, with four replications. The variables analyzed were: germination percentage, first count and germination speed index (GSI), as well as length and dry mass of shoots and primary roots of seedlings. C. fairchildiana seeds germinate in the dark and in all light regimes, regardless of the temperature used and are considered neutral photoblastic. To evaluate the effect of these seeds is recommended temperature of 30°C in the regime of white light, except for the test seedling dry weight, which indicated the green light, far-red or dark.

Initial growth in seedlings ofAdenanthera pavoninaL. for different substrates

Adenanthera pavonina L., a species that produces great quantities of viable seeds, is widely used in the reclamation of degraded areas. The aim was to study the effect of different substrates on the emergence and initial growth of seedlings of A. pavonina. The experiment was carried out at the Centre for Agrarian Science of the Federal University of Paraiba, in Areia, Pariba, Brazil. The experimental design was completely randomised (CRD) with the treatments composed of 14 substrates: sand, compost, fine vermiculite, sawdust, carbonised rice hull, sand + compost in a 1:1 ratio, sand + sawdust in a 1:1 ratio, sand + cured cattle manure in a 1:1 ratio, compost + sawdust in a 1:1 ratio, compost + cattle manure in a 1:1 ratio, fine vermiculite and sand in a 1:1 ratio, fine vermiculite + sawdust in a 1:1 ratio, fine vermiculite + compost in a 1:1 ratio, and fine vermiculite + cured cattle manure in a 1:1 ratio, in four replications of 25 seeds. The following were evaluated: emergence, first count, speed of emergence index, and length and dry weight of the roots and shoots. Given the results, it was found that the sand, compost and fine vermiculite substrates, as well as the mixtures of sand + compost, compost + sawdust and fine vermiculite + sawdust in a 1:1 ratio are the most efficient for promoting the emergence and initial growth of seedlings of A. pavonina.

Morpho-physiological analyses of Allamanda blanchetii A. DC. seedlings under water deficit

The Allamanda blanchetii belongs to the Apocynaceae family, being an ornamental species popularly known as allamanda-roxa and is endemic to the Caatinga. The aim of this research was to evaluate the growth, gas exchange, relative water content, and stomatal density of A. blanchetii under water stress conditions. The experimental design was completely randomized with six levels of the maximum water holding capacity (MWHC) (100%, 80%, 60%, 40%, and 20%) with eight replications. Weekly, it was performed the evaluations of plant height and number of leaves. The results for water stress treatment in the A. blanchetii plants show that they develop better in the water levels of 100% and 80% of the MWHC, without presenting significant morphological and physiological changes. In turn, 20% of the MWHC does not allow the survival of the A. blanchetii plants. The water restriction negatively interfered in the gas exchange in the treatment of 60% and 40% of the MWHC. Therefore, it can be concluded that the A. blanchetii plants grow satisfactorily in 100% and 80% of the MWHC, ensuring the growth and survival during the drought period. The water availability to which the plants were submitted does not influence the total chlorophyll and relative water content of leaves. Gas exchanges are adversely affected at levels of water availability below 80% of the MWHC.