Caracterización ecofisiológica de plantas juveniles de aguacate ‘HASS’ (persea americana VAR. ‘HASS’) bajo distintas condiciones de luz solar

Abstract

Se evaluó el efecto de distintos niveles de radiación solar en plantas juveniles de aguacate ‘Hass’ a partir de sombras artificiales en un ensayo controlado y sombras naturales en un cultivo mixto. Las variables evaluadas sugieren que las plantas evaluadas tienen características de plantas facultativas para crecer en bajas radiaciones solares.

Abstract The effect of different levels of solar radiation on juvenile 'Hass' avocado plants was evaluated from artificial shadows in a controlled experiment and natural shadows in a mixed crop in Pasca (Cundinamarca, Colombia). Physiological variables such as the rate of CO2 assimilation, transpiration and stomatal resistance related to gas exchange were evaluated; Rapid light response curves (RLCs) and non-photochemical quenching curves (NPQ) were also made by measurements of chlorophyll fluorescence. The morphological and anatomical response of the plants was characterized by cross - sectioning of leaves and in vivo growth measurements. Physiological, anatomical and morphological differences were found in plants exposed to different levels of solar radiation. Plants submitted to 50% solar radiation presented lower values of maximal rate of electron transference (ETRmax) and a consequent increase in energy dissipation by the non-photochemical pathway. At stomatal level plants under 65% and 50% solar radiation treatments had less stomatal resistance compared to plants exposed to total solar radiation. As for the morphology of the plants, the treatment with less solar radiation promoted the growth in height and the leafy development of the canopy. A relationship was found between the opening of the canopy and the light intensity, showing differential conditions of solar radiation given the establishment of the plants as a mixed crop. It was found a relationship between the physiological variables evaluated and the levels of solar radiation of the evaluated plants with positive correlations between ETR and solar radiation levels. Assessed physiological variables suggest that ‘Hass’ avocado young plants has characteristics of facultative plant to growth under little sun light.