Biomass and morphological parameters of lemon verbena (Aloysia triphylla) under different shading levels during different seasonal conditions

Abstract

Shading greenhouse may be an effective method to achieve a suitable environment for crop growth in subtropical regions. The aim of this study was to evaluate the production of leaves and branches as well as the morphological parameters of height and leaf area of the species Aloysia triphylla, under different shading levels throughout the seasons of the year. A randomized block design in factorial scheme 3x4x6, i.e., three levels of shading (0%, 30% and 50%), four seasons (summer, autumn, winter and spring) and six collection in each season (15, 30, 45, 60, 75 and 90 days after the beginning of each season), with four replications, was used. All evaluations were performed in 2012, since in the first evaluation (summer) the plants had 65 days after transplanting and the last evaluation (spring) the plants had 315 days after transplanting. The dry matter of leaves and branches, leaf area, and plant height were evaluated. The production of the dry matter of leaves and branches, and height and leaf area for the species Aloysia triphylla is influenced by shading levels and the seasons of the year. The variables are highly dependent on the seasonality of meteorological elements such as temperature, solar radiation, rainfall, and frost. In an environment with 0% shading, the dry matter production of leaves was 60.8 % higher in the spring, than those observed for the 30% and 50 % of shading, while this levels resulted higher production in the summer. We showed that the use of shading screens in order to attenuate the solar radiation in places or seasons where there is high light intensity is an effective method to achieve higher production of leaves, which is important source for the oil production.

Effect of season and irrigation on the chemical composition of Aloysia triphylla essential oil

“…The plant material was placed in a 5,000-mL volumetric Temporal and spatial variation in the composition, relative proportion, and scale of each component in essential oils is caused by seasonal and daily changes (Chagas et al, 2011;Schwerz et al, 2015). Several reports (Schwerz et al, 2015;Prochnow et al, 2017;Schmidt et al, 2017) have discussed the variation in biomass, content, and composition of A. triphylla essential oil, attributing them to the climatic factors.…”

“…One of the physiological functions of secondary metabolites is to assist/protect plants against environmental stresses (Prochnow et al, 2016). Studies have shown that the synthesis of these metabolites is affected by the local climate, including factors such as rainfall, temperature, relative humidity, and photoperiod (Paulus et al, 2013a;Schmidt et al, 2017). Among the meteorological elements, rainfall in particular affects the production of secondary metabolites in these plants, especially the composition of essential oils (Brotel et al, 2010).…”