Tolerância de mamona a zinco avaliada por fluorescência de clorofila e nutrição das plantas

Abstract

A medida da fluorescência de clorofila pode ser uma ferramenta útil para detectar alterações no aparato fotossintético das plantas. Considerando que a detecção precoce da contaminação de zinco em plantas é essencial para o monitoramento ambiental, este trabalho objetivou avaliar o estresse causado por esse nutriente em plantas de mamona (Ricinus communis), utilizando a técnica da fluorescência de clorofila. As alterações provocadas pelo Zn nos pigmentos fotossintéticos e na composição mineral das plantas foram também estudadas. Plantas de mamona foram cultivadas durante 28 dias em solução nutritiva com cinco doses de Zn (100, 200, 300, 400 e 600 µmol L -1 ), além de um controle contendo 0,380 µmol L -1 do elemento. A fluorescência de clorofila detectou alterações temporais promovidas pelo acúmulo de Zn nas plantas e evidenciou-se útil na detecção precoce da toxicidade do elemento em plantas de mamona. Apesar do declínio no seu estado nutricional, a mamona apresentou relativa tolerância à toxicidade a doses elevadas de Zn, indicando ser essa espécie uma alternativa atraente para revegetação ou remediação de áreas contaminadas.Termos de indexação: Ricinus communis, elemento-traço, poluição do solo, fotossíntese.

Changes in root morphology and dry matter production in Pfaffia glomerata (Spreng.) Pedersen accessions in response to excessive zinc

“…However, independently of the Zn level tested, this accession showed chlorotic leaves and low growth during the evaluation periods, indicating that it was not adapted to the hydroponic system used, when compared to the other accessions. The observed typical symptoms of inhibition of growth of P. glomerata by excess Zn have also been reported for other species such as Sedum alfredii (Li et al, 2009), Ricinus communis (Marques & Nascimento, 2014), Triticum aestivum (Li et al, 2012) and Zea mays (Alonso-Blázquez et al, 2015).…”

“…Sofo et al (2013) observed that the Cd/Cu/Zninduced changes in root morphology of Arabidopsis were caused by a hormonal imbalance, mainly controlled by the auxin/cytokinin ratio. It has been indicated that Zn toxicity depends on plant species and growth stage, and that growth inhibition and biomass reduction are common responses of plants to excess Zn (Li et al, 2009;Li et al, 2012;Marques & Nascimento, 2014;Alonso-Blázquez et al, 2015).…”

<b>Metabolic alterations and X-ray chlorophyll fluorescence for the early detection of lead stress in castor bean (<i>Ricinus communis</i>) plants

“…Use of the Fr/FFr ratio allowed detection of changes in PSII when plants showed no visual symptoms of toxicity. Therefore, chlorophyll fluorescence is a useful tool for monitoring Pb toxicity in castor bean plants, corroborating results found in studies of Cd toxicity (Silva, Nascimento, Gouveia-Neto, & Silva-Jr., 2012;Marques & Nascimento, 2013;, As toxicity (Stoeva, Berova, & Zlatev, 2004;(Silva et al, 2015), Ni toxicity (Gopal, Mishra, Zeeshan, Prasad, & Joshi, 2002;Mishra & Gopal, 2008), Cu and Hg toxicities (Ventrella, Catucci, Piletska, Piletsky, & Agostiano, 2009), Zn (Cherif et al, 2010;Marques & Nascimento, 2014;Marques et al, 2017) and Pb toxicity (Marques et al, 2017).…”

Mineral composition, chlorophyll fluorescence and zinc biofortification in Vigna unguiculata fertilized with bulk and nanoparticulate zinc oxides

“…Biomass production, plant nutritional composition, and biochemical analyzes are often adopted to assess fertilizers' effects on crops (Vassilev et al 2011;Marques and Nascimento 2014;Tiecher et al 2016;Bradfield et al 2017). The chlorophyll a fluorescence technique, for example, is a useful tool for evaluating crop performance under agronomic Communicated by O. Ferrarese-Filho.…”

“…The opportunity for early assessment of deficiency or toxicity of elements in plants is one of the main advantages of this technique (Faseela et al 2020). For instance, Marques and Nascimento (2014) reported alterations in the photosynthetic efficiency of castor bean plants exposed to Zn even before phytotoxicity symptoms could be visualized.…”