Análise de crescimento em Heteranthera reniformis, sob diferentes teores de Ca, Mg e S

Abstract

RESUMOO objetivo deste trabalho foi estudar o crescimento, alocação de biomassa e teores de nutrientes em Heteranthera reniformis Ruiz & Pav., sob o efeito de diferentes concentrações de Ca, Mg e S. As plantas foram cultivadas em vasos plásticos preenchidos com pedra rolada, em soluções nutritivas a 80% da concentração original de Sarruge, correspondente à solução-base. O experimento foi desenvolvido em delineamento experimental inteiramente casualizado, com quatro teores (0%, 25%, 50% e 75% da solução base de 80%) avaliados em Ca, Mg e S, além da testemunha (solução-base), com quatro repetições no período de 35 dias em casa de vegetação. O aumento dos teores de Ca na solução propiciou uma redução significativa na área foliar. As maiores áreas foliares ocorreram em soluções a 25% de Ca e 50% de Mg e S. A maior proporção de biomassa seca está no caule, exceto a 25% de Ca (40 mg L -1 ) que propiciou maior área foliar e área foliar específica. Entre os teores de Mg na solução, as maiores biomassas foram observadas a 50% de Mg (19,2 mg.L -1 ) e, para o S, não houve diferenças significativas, exceto a 0%. A solução com 160 mg L -1 de Ca propiciou maior concentração de Ca na folha (56,6 g kg -1 ). Os teores de Ca, Mg e S em solução corresponderam a um aumento proporcional na planta. Os teores de enxofre nas folhas e nos caules aumentaram com a concentração de S na solução, enquanto o teor nas raízes reduziu nas concentrações entre 12,8 e 38,4 mg L -1 .Palavras-chave: planta aquática, planta daninha, nutrientes e biomassa. ABSTRACT GROWTH ANALYSIS IN HETERANTHERA RENIFORMIS UNDER DIFFERENT CONTENTS OF Ca, Mg AND SThe objective was to study the growth, biomass allocation and concentration of nutrients in Heteranthera reniformis Ruiz & Pav. under the effect of different concentrations of Ca, Mg and S. The plants were cultivated in plastic pots fulfilled with rolled stone, in nutrient solutions of 80% of the original concentration of Sarruge. The experiment was carried out in a complete randomized design, with 4 contents (0, 25, 50 and 75% of the solution base ) evaluated in Ca, Mg and S, plus the control (100% of the solution base), with 4 replicates in the period of 35 days in greenhouse. The increase of contents of Ca produced significant reduction in the leaf area. The largest areas leaf occurred in solutions of 25% of Ca and 50% of Mg and S. The largest proportion of dry biomass was found in the stem, except with 25% of Ca (40 mg L -1 ) in solution that produced larger leaf area and larger specific leaf area. Among different Mg contents, larger biomasses were observed at 50% of Mg (19,2 mg L -1 ) and, for S, there were not significant differences, except at 0% of S in solution. The solution with 160 mg.L -1 of Ca produced the largest concentration of Ca in leaf (56,6 g kg -1 ). The contents of Ca, Mg and S in solution corresponded to a proportional increase in the plant. The contents of sulfur in leaves and in stems increased with the concentration of S, whereas the content in roots reduced in the concentrations betw...

Multi-mixture herbicides provide management strategies in the control of the aquatic weed Heteranthera reniformis

“…However, the control efficiency of these products in areas with perennialized plants has not been verified by the producers, since, in many cases, there is regrowth and consequent reinfestation (Bianchini et al 2010). In general, herbicides with low persistence in the soil are not efficient in controlling the germination of seeds that may have remained in the soil, as is the case with the seeds of the species under study (Domingos et al 2006;Pellegrini and Horn 2017;Li et al 2018). In addition, the species also has a special cuticle on the leaves, which makes it difficult for the herbicide to penetrate the plant, and consequently, provide effective control (Karov et al 2013;Pellegrini and Horn 2017).…”

“…Aquatic plant species are important components in water resources and the ecosystem, as they play a fundamental role in the production of biomass, promote suitable habitats for many organisms, and support the oviposition and refuge of fish and other animals (Caffrey et al 2010). However, if this aquatic vegetation finds a favorable habitat for its development and presents excessive growth, it can cause problems in terms of crop management in irrigated areas, competition between plants (weed vs. crop), waterway transport, energy production, among others (Domingos et al 2006;Pellegrini and Horn 2017;Singh et al 2020), and being considered an aquatic weed. These aquatic weeds may exhibit characteristics of rapid population growth and better adaptation to environmental conditions (Pellegrini and Horn 2017, being able to suppress less aggressive plants desirable to maintain the diversity of the ecosystem.…”

“…Going further, when the water level rises, the plant detaches from the soil and floats, characterizing reproduction by vegetative propagation, through which extensive floating mats of the weed are formed (Champion et al 2010). H. reniformis stands out in competing for resources and causing losses, mainly in flooded rice fields, seedling nurseries, drainage and irrigation channels, lakes and streams (Domingos et al 2006;Hussner 2012;Linke et al 2014;Pellegrini and Horn 2017). Preventive control is the best alternative to minimize its proliferation, since water and machinery that accumulate sludge are the main dispersing agents of its seeds (Champion et al 2010).…”