Increase in lettuce (Lactuca sativa L.) production by foliar calcium application

Resumo

A deficiência de cálcio (Ca) nas plantas afeta o crescimento das folhas jovens e
desencadeia sintomas associados à ruptura celular. A aplicação foliar de Ca é
recomendado porque fornece o nutriente diretamente ao órgão de interesse durante
estágios críticos de crescimento. A literatura sobre a eficiência da aplicação foliar de Ca é
controversa porque tal eficiência depende da fonte de Ca, dose aplicada e
cultura investigada. Objetivo: O presente estudo teve como objetivo avaliar se o Ca foliar
a aplicação interfere no acúmulo de biomassa e na concentração de Ca na folha. O
os tratamentos consistiram de um planejamento fatorial e aplicação foliar de três fontes de Ca
(óxido de cálcio, cloreto de cálcio, quelato de cálcio) em quatro doses, bem como um controle. Resultados: A maioria das fontes e dosagens aumentou o número de folhas, e
três tratamentos aumentaram a biomassa da parte aérea. O acúmulo de Ca nas paredes celulares de
certos tratamentos foram observados usando espectroscopia de raios-X de energia dispersiva (SEM
EDS) e testes histoquímicos com vermelho de rutênio. A eficiência do Ca foliar
depende da fonte e dosagem aplicada, as fontes de Ca mostraram
diferenças significativas.

Abstract

Backgound: Calcium (Ca) deficiency in plants affects the growth of young leaves and
triggers symptoms associated with cell disruption. The foliar application of Ca is
recommended because it provides the nutrient directly to the organ of interest during
critical growth stages. The literature on the efficiency of foliar Ca application is
controversial because such efficiency depends on the Ca source, applied dose and
investigated culture. Objective: The present study aimed to assess whether foliar Ca
application interferes with biomass accumulation and Ca concentration in the leaf. The
treatments consisted of a factorial design and the foliar application of three Ca sources
(calcium oxide, calcium chloride, calcium chelate) in four doses as well as a control
group. Results: Most of the sources and dosages increased the number of leaves, and
three treatments increased the shoot biomass. Ca accumulation in the cell walls of
certain treatments was observed using energy dispersive X-ray spectroscopy (SEM
EDS) and histochemical tests with ruthenium red. The efficiency of foliar Ca
application is dependent on the source and applied dosage, the Ca sources showed
significant differences, with CaCl2 at the recommended dosage showing the optimal
cost benefits and efficiency compared with CaO and Ca chelate. Conclusions: Spraying
increased the Ca can promote biofortification of plant foods by increasing Ca
concentrations in the leaves concentration and accumulation of biomass because of Ca
deposition in the cell wall as Ca pectate. Therefore, Ca spraying decrease post-harvest
losses and improved durability and increase the time available for marketing the
produc