Modifications in vapor diffusion resistence of leaves and water relations in barbados cherry plants under water stress

Abstract

Young sexually and assexually propagated Barbados cherry plants were submitted to water deficit (20 days without irrigation). During this period the accumulation of proline, water potential of branches, osmotic potential, the relative water content of leaves, the leaf diffusive resistance, the transpiration rate and leaf temperature in the cuvette were determined. In addition, photosynthetically active radiation (PAR) and vapor pressure deficit (VPD) were measured in the porometer cuvette. The concentration of proline for both types of plants began to increase on the fifth day without watering, and reached 38.1 times the concentration in the control plants grown from seeds and 26.4 times the concentration in grafted plants on the tenth day without watering. The lowest levels of leaf water potential in the plants suffering from severe water stress varied from -4.5 to -5.7 MPa, the lowest values being observed in the sexually propagated plants. These plants also showed the highest values for transpiration (0.9 mmol.m-2.s-1) and proline concentration (20.42 mg.g-1 DM), the lowest for relative water content of the leaves (38.4%) and diffusive resistance (940 s.m-1) at the end of the experiment. The Barbados cherry plants developed strategies for surviving drought, with differences between various characteristics, resulting from prolonged stress, which significantly influenced the parameters evaluated, with the exception of leaf temperature.

Crescimento de combinações copa - porta-enxerto de citros sob estresse hídrico em casa de vegetação

“…De acordo com Nogueira et al (2001), genótipos que apresentem diversidade na resposta ao estresse hídrico constituem excelentes materiais para serem utilizados em programas de melhoramento genético. Vários caracteres fisiológicos podem ser empregados na avaliação das respostas das espécies vegetais ao estresse hídrico.…”

Physiological limitations in two sugarcane varieties under water suppression and after recovering

“…The negative effects of water shortage over biochemical, physiological, and morphological processes can be verified in all parts of the plant. In situations of water restriction, common physiological alterations include reduced leaf water potential and the relative water content (Nogueira et al 2000, Graça et al 2010, gas exchange, photosynthesis, as well as reduced maximum quantum efficiency of the photosystem II (Inman-Bamber and Smith 2005, Silva et al 2007, Jaleel et al 2009, Gonçalves et al 2010, Graça et al 2010. As a consequence, metabolic changes such as increase in osmoregulators (Nogueira et al 2001, Guimarães et al 2008, Silva et al 2009, Medeiros et al 2012) may occur along with significant alterations on the plant growth, in response to the lower turgor pressure in the cells (Hessini et al 2009).…”

Avaliação morfofisiológica em mudas de Handroanthus impetiginosus (Mart. ex DC.) Mattos durante a rustificação

“…A diferença de temperatura foliar entre plantas submetidas ou não ao estresse fundamentase no status hídrico, no comportamento estomático e na perda de calor latente por meio da transpiração, apresentando variações quanto à tolerância em função da espécie, do ambiente, da intensidade, da duração e da hora do dia (Nogueira et al, 2001). …”