Relação Hídrica E Teor De Clorofila Em Dois Cultivares De Arroz Submetido À Deficiência Hidrica E Adubação Silicatada.

Abstract

RELAÇÃO HÍDRICA E TEOR DE CLOROFILA EM DOIS CULTIVARES DE ARROZ SUBMETIDO À DEFICIÊNCIA HIDRICA E ADUBAÇÃO SILICATADA. ADRIANA LIMA MORO1; FERNANDO BROETTO2 E EDEMAR MORO11Departamento de Ciências Agrárias - Universidade do Oeste Paulista – UNOESTE/Presidente Prudente (SP), adrianamoro@unoeste.br; edemar@unoeste.br2Departamento de Química e Bioquímica – Instituto de Biociências – UNESP/Botucatu (SP). broetto@ibb.unesp.br 1 RESUMO Plantas submetidas a deficiência hídrica comprometem os processos fisiológicos e a capacidade de produção. O silício é um nutriente que pode proporcionar melhor desenvolvimento às plantas de arroz cultivadas em ambientes com deficiência hídrica. Este elemento diminui as perdas de água por transpiração, melhorando assim as funções fisiológicas da planta. O objetivo deste trabalho foi estudar a relação entre deficiência hídrica e o efeito do silício em dois cultivares de arroz (Curinga e IAC 202) sob pigmentos, conteúdo relativo de água (CRA), transpiração e matéria seca. O delineamento experimental foi em blocos casualizados em esquema fatorial 4 x 2, com quatro repetições. Os tratamentos foram constituídos por quatro potenciais mátricos de água no solo (-10, -30, -50 e -70 kPa) combinadas com dois corretivos da acidez do solo (calcário dolomítico e silicato de cálcio e magnésio). Houve aumento do conteúdo de clorofila a com a adição de silício no cultivar Curinga na fase de florescimento. O CRA para ambos os cultivares e em todas as fases fenológicas avaliadas apresentaram aumento com a aplicação de silício. A taxa de transpiração (E) foi menor em ambos os cultivares a partir da fase de emborrachamento nas maiores tensões -50 e -70 kPa. Houve incremento da matéria seca com a aplicação de silício para ambos os cultivares na fase de enchimento de grãos, mesmo com a intensidade da deficiência hídrica. Palavras chave: Conteúdo relativo de água, potenciais, transpiração. MORO, A. L.; BROETTO, F.; MORO, E.WATER RELATIONSHIP AND CHLOROPHYLL CONTENT IN TWO RICE CULTIVARS UNDER WATER STRESS AND SILICON FERTILIZATION 2 ABSTRACT Plants under water stress jeopardize physiological processes and production capacity. Silicon is a nutrient which provides better growth to rice plants grown in an environment under water stress. This element reduces losses of water by transpiration, improving the physiological functions of the plant. The objective of this study was to evaluate the relationship between water stress and the silicon effect on two rice cultivars under pigments, to determine relative water content (RWC), transpiration and dry matter. A completely randomized and factorial (4x2) design was used with four replicates. Treatments consisted of four matric potential of water in the soil water (-10, -30, -50 and -70 kPa) in association with two amendments for soil acidity (lime and magnesium and calcium silicate). An increase was observed in the content of chlorophyll a by the addition of silicon to cv. Curinga during the flowering stage An increase in the RWC for both cultivars and in all phenological phases was observed after silicon addition. Transpiration rate was lower in both cultivars as of the booting stage at the higher tensions of -50 and -70kPa. An increase in dry matter for both cultivars after silicon addition was observed during the grain filling stage even considering the intensity of water stress. Keywords: relative water content, potential, transpiration.

Growth and gas exchanges of arugula plants under silicon fertilization and water restriction

“…This effect of water stress had already been reported by Cechin et al (2010), who observed reduction the physiological variables photosynthesis, stomatal conductance and transpiration of sunflower leaves due to water stress. In addition, as observed in other studies (Moro et al, 2015;Teodoro et al, 2015), Si has played fundamental role in the improvement of physiological aspects in plants.…”

Potential of calcium silicate to mitigate water deficiency in maize

“…In rice, an increase in grain production has been observed after application of calcium silicate, particularly when the plants were exposed to lower amounts of water available in soil. Thus, the lower the field capacity of soil, the greater the response of plants to silicon (Moro et al 2015). The H 4 SiO 4 monomer is the silicon compound present in the liquid phase of soil in the pH range of 4 to 9 (Marschner 1995), which is absorbed by plant roots in a passive or active manner mediated by specific membrane transporters.…”

“…In order to mitigate the effects of abiotic and biotic stress, silicon exerts several specific functions (Moro et al 2015), and its absorption by plants has several benefits, protecting against saline stress, metal toxicity, water deficit, radiation damage, high temperature and frost and regulating nutrient balance. These beneficial effects are attributed to the high accumulation of silica in plant tissues (Ma 2004).…”

Analysis of Leaf Pigments of SJ-02 Cocoa Seedlings Under Different Irrigation Depths and Cultivation Containers

“…Under water stress, a decrease in chlorophyll content is commonly observed, which consequently influences the photosynthetic system of the plant (Silva et al, 2014). In addition, the decrease in these photosynthetic pigments can lead plants to leaf senescence, reducing their life cycle and this reduction is directly linked to limited capacity and greater degradation of total chlorophyll contents, because under water stress conditions, plants alter their routes to avoid photoinhibition and photooxidation of the photosynthetic apparatus (Pincelli, 2010;Moro et al, 2015).…”