Claudiana Moura dos Santos

Gas exchange alteration caused by water deficit during the bean reproductive stage

Neste trabalho, se analisaram as trocas gasosas das folhas e parâmetros de produtividade de feijao (Phaseolus vulgaris, L.) submetido a dois periodos de deficiencia hidrica e se empregaram tres regimes hidricos, a saber: W1 (1,0 ETo durante todo o ciclo da cultura); W2 (1,0 ETo ate a floracao e suspensao da irrigacao do 37 ao 51o dia apos a semeadura (DAS), correspondendo a fase de floracao) e W3 (alem da fase reprodutiva tambem se aplicou um deficit hidrico durante a fase vegetativa). A fotossintese foi um dos principais fatores fisiologicos afetados pelo deficit hidrico devido nao so ao fechamento estomatico, mas, tambem, a reducao da eficiencia de carboxilacao, resultante de um dano metabolico; este efeito, contudo, foi neutralizado 24 h apos reidratacao. Durante a floracao o deficit hidrico causou reducao sensivel da produtividade da cultura, com reducao tambem do numero de vagens e numero de sementes por vagem, independentemente do deficit durante a fase vegetativa, porem a massa de 100 sementes nao se alterou em nenhum dos regimes; esses resultados sugerem que o deficit hidrico leva a uma reducao dos fotoassimilados prejudicando a producao final; no entanto, uma vez formada, a semente se desenvolve plenamente, sendo esta uma estrategia da planta em produzir poucas sementes, mas viaveis para perpetuar a especie, mesmo sob condicoes de estresse.

Enraizamento de estacas de Pau-Brasil (Caesalpinia echinata Lam.) tratadas com ácido indol butírico e ácido naftaleno acético

The pau-brasil tree (Caesalpinia echinata Lam.) have a high cultural value in Brazil and its seed propagation is very difficult because of its rapid losses of germination potential. Cuttings propagation has been considered as alternative method to propagate forest species that seed propagation is poor. The objectives of this study were to determine the effects of indole-3-butyric acid (IBA) and naphthalene acetic (NAA) acid on the adventitious root formation on stem cuttings of pau-brasil. Cuttings with around 12cm length, with two pars of leaves, received a basal treatment of 0; 6,25; 12,50; 25 and 50mM IBA and NAA as solution form or 0, 1,250, 2,500, 5,000, 10,000mg Kg-1 as powder form. All cuttings were planted in cell trays containing sand and placed under greenhouse mist (90-95% relative humidity). After 120 days, cuttings were assessed for survival, foliar retention, callus formation and roots formation. There were high survival rate (up to 70%) of the cuttings. Callus formation was not correlated to auxin concentration. The utilization of liquid 25mM of IBA and NAA promoted the highest percentage of root formation, around 16%. The high survival rate associate with low percentage of root formation suggests that the cuttings may need longer time in greenhouse in order to stimulate root formation.

Primeiro registro de Pachycoris torridus (Scopoli, 1772) (Hemiptera: Scutelleridae) em pinhão-manso (Euphorbiaceae) em Alagoas, Brasil

The occurrence of Pachycoris torridus (Scopoli) (Hemiptera: Scutelleridae) in Igaci (in the state of Alagoas, Brazil), is observed attacking the physic nut (Jatropha curcas L.) The insect, until then not verified in the region, takes economic relevancy considering the nature of damage, causing infestation in 100% plants.

Photosynthetic capacity and water use efficiency in Ricinus communis (L.) under drought stress in semi-humid and semi-arid areas

Castor bean is one of the crops with potential to provide raw material for production of oils for biodiesel. This species possess adaptive mechanisms for maintaining the water status when subjected to drought stress. A better understanding these mechanisms under field conditions can unravel the survival strategies used by this species. This study aimed to compare the physiological adaptations of Ricinus communis (L.) in two regions with different climates, the semi-arid and semi-humid subject to water stress. The plants showed greater vapor pressure deficit during the driest hours of the day, which contributed to higher values of the leaf temperature and leaf transpiration, however, the VPD(leaf-air) had the greatest effect on plants in the semi-arid region. In both regions, between 12:00 p.m. and 2:00 p.m., the plants presented reduction in the rates of photosynthesis and intracellular CO2 concentration in response to stomatal closure. During the dry season in the semi-arid region, photoinhibition occurred in the leaves of castor bean between 12:00 p.m. and 2:00 p.m. These results suggest that castor bean plants possess compensatory mechanisms for drought tolerance, such as: higher stomatal control and maintenance of photosynthetic capacity, allowing the plant to survive well in soil with low water availability.