Photo-selective nets and potassium concentrations on Costus lasius crop

Abstract

The practice of using different photo-selective nets, associated with the technique of fertigation, represents a new agrotechnological concept that aims to promote specific physiological responses for growth and production, which are regulated by light. The aims of the study were to evaluate the effect of photo-selective nets and potassium concentrations in the fertigation solution on the horticultural performance of Costus lasius. The study was conducted at the Universidade de São Paulo, ESALQ, Piracicaba, SP, Brazil. Three experiments were carried out separately to evaluate five potassium concentrations in the fertigation solution (40, 80, 120, 160 and 200 mg L-1) under three colours of photo-selective nets (red, blue and black) in a randomized block design, with five repetitions. The variables plant height and numbers of leaves, stems and flower buds were evaluated. The data were submitted to the joint analysis of experiments. The association between the K+ concentration of 200 mg L-1 and the black photo-selective net results in higher stem and inflorescence production.

Ambientes de luz e substratos orgânicos no crescimento e qualidade de mudas de noni / Light environments and organic substrates in the growth and quality of noni seedlings

“…Observa-se que plantas cultivadas sob malha preta foram superiores 20,45 % ao NF quanto comparadas àquelas crescidas a pleno sol (Figura 1). Corroborando com este resultado, Sampaio et al (2020) relataram maiores NF em plantas de Costus lasius cultivada sob baixa disponibilidade de radiação solar obtida em ambiente com malha preta. Este efeito provavelmente deve-se ao alto nível de sombreamento, fazendo com que a planta invista em maior número de folhas, a fim de aumentar a superfície e eficiência fotossintética (Felsembugh et al, 2016).…”

Pigments in flower stems of lisianthus under different photoselective shade nets

“…The mechanism of colored shades is based on the distinct filtering of sunlight together with the incorporation of chromatic elements during manufacture to provide physical protection of crops by shading. In this way, plant physiological responses can be altered, through photosynthetic and photo-morphological processes, by manipulating the radiation spectrum (Sivakumar et al, 2018;Sampaio et al, 2020). In Brazil, some regions have a similar average number of sunny days to those of the Middle East, such as the Central West and Northeast regions.…”

“…In foliage such as Codiaeum variegatum and Aglaonema commutatum, the use of green, yellow, and red color shades has been evaluated, demonstrating that high levels of anthocyanin and carotenoids were obtained using the red color shade . The ornamental, Costus lasius, a tropical plant grown in pots, the use of a black color shade associated with a dose of 200 mg L -1 of potassium resulted in the greater production of flower buds (Sampaio et al, 2020). Lisianthus for cut flowers, an increase in the length of the stem was observed using the red color shade, while using the blue shade there was a reduction in the diameter of the stem (Almeida et al, 2016).…”