Copper uptake, accumulation and physiological changes in adult grapevines in response to excess copper in soil.

Publicada online em 24 de setembro

Iron fertilization to enhance tolerance mechanisms to copper toxicityof ryegrass plants used as cover crop in vineyards.

Ryegrass (Lolium perenneL.) is a plant species that can express mechanisms of tolerance to copper (Cu)toxicity. Therefore, the agronomical approach of intercropping system with ryegrass may represent apromising tool to limit the onset of Cu toxicity symptoms in the other intercropped plants species,particularly when an inadequate nutrient availability like iron (Fe) shortage is also concurrently present.This study aimed at assessing the mechanisms involved in the mitigation of Cu phytotoxicity and thestress effects on plant growth, root morphology and nutrition of ryegrass fertilized with two different Fesources. To this purpose, seedlings of ryegrass were hydroponically grown for 14 days in controlledconditions with 4 different levels of Cu (0.2, 5.0, 25 and 50mM) and with either 100mM Fe-EDDHA or Fe-EDTA. Results show that high levels of Cu availability enhanced the root content of organic anions as wellas the root exudation. Different Fe fertilizations at the condition of 50mM Cu induced changes in rootphenolic compounds, citrate and fumarate contents and the exudation pattern of phenolic compounds.Differences in plant growth were not observed between the two Fe sources, although Cu concentration inplant tissue fed with Fe-EDTA was lower in the condition of 50mM Cu. The enhanced root exudation ofCu-complexing organic compounds (including phenolics) in ryegrass plants when exposed to excessiveCu availability could be at the basis of the ameliorated edaphic rhizosphere conditions (lower Cuavailability). For this reason, from the agronomical point of view ryegrass plants used in intercroppingsystems with crops like vine plants could represent a promising strategy to control Cu toxicity invineyard soils. Further studies under thefield conditions must be taken to support presentfindings.©2019 Elsevier Ltd. All rights reserved

Oxidative stress as markers in identification of aluminum-tolerant peach tree rootstock cultivars and clonal selections.

Abstract: Peach rootstock and scion cultivars are selected in breeding programs considering resistance to pests and diseases, salt tolerance, drought tolerance, and vigor. However, rootstock tolerance to aluminum (Al), which is markedly present in tropical and subtropical soils of the world, is not considered. Thus, it is essential to define potential markers that can contribute to the selection of Al-resistant or Al-tolerant peach rootstocks. The objective of this study was to identify Al-tolerant peach tree rootstock cultivars and clonal selections using physiological and oxidative stress variables. A completely randomized experimental design was used in a 13 (rootstock cultivars and clonal selections) × 2 (with and without Al) factorial arrangement, with three replications. Nursery peach trees of own-rooted ‘BRS Mandinho’ (without rootstock) and nursery trees of ‘BRS Mandinho’ grafted on different rootstock cultivars and clonal selections were grown in a hydroponic system, consisting of two treatments, with and without 100 mg L-1 of Al. Dry biomass, photosynthetic variables, pigment concentration, hydrogen peroxide content, membrane lipid peroxidation, and activity of the antioxidant enzymes were evaluated. The total dry matter production of the own-rooted ‘BRS Mandinho’ trees and the SS-CHI-09-39 and SS-CHI-09-40 selections is affected by the Al presence, representing a decline of 35.4, 37.2, and 24.4 %, respectively, compared to the treatment with Al. The highest total dry matter production in Al presence was observed for the ‘Sharpe’ rootstock. ‘Capdeboscq’, DB-SEN-09-23, FB-ESM-09-43, JB-ESM-09-13, JAH-MAC-09-77, SAS-SAU-09-71, and VEH-GRA-09-55 rootstock selections are tolerant to Al. The use of physiological and biochemical variables shows potential for the selection of clonal rootstocks tolerant or resistant to Al. Resumo: Os porta-enxertos e cultivares de pessegueiro são selecionados em programas de melhoramento considerando a resistência a pragas e doenças, tolerância ao sal, tolerância à seca e vigor. Contudo, a tolerância do porta-enxerto ao alumínio (Al), que está marcadamente presente nos solos tropicais e subtropicais do mundo, não é considerada. Assim, é essencial definir potenciais marcadores que possam contribuir para a seleção de porta-enxertos de pessegueiro resistentes ou tolerantes ao Al. O objetivo deste estudo foi identificar cultivares de porta-enxertos de pessegueiro tolerantes ao Al e seleções clonais utilizando variáveis fisiológicas e de estresse oxidativo. O delineamento experimental utilizado foi inteiramente casualizado, em arranjo fatorial 13 (cultivares de porta-enxertos e seleções clonais) x 2 (com e sem Al), com três repetições. Pessegueiros de mudas 'BRS Mandinho' de raiz própria (sem porta-enxerto) e mudas de 'BRS Mandinho' enxertados em diferentes cultivares de porta-enxertos e seleções clonais foram cultivados em sistema hidropônico, composto por dois tratamentos, com e sem 100 mg L- 1 de Al. Foram avaliadas biomassa seca, variáveis fotossintéticas, concentração de pigmentos, teor de peróxido de hidrogênio, peroxidação lipídica de membrana e atividade de enzimas antioxidantes. A produção total de matéria seca das árvores 'BRS Mandinho' de raiz própria e das seleções SS-CHI-09-39 e SS-CHI-09-40 é afetada pela presença de Al, representando um declínio de 35,4, 37,2 e 24,4 %, respectivamente, em comparação ao tratamento com Al. A maior produção total de matéria seca na presença de Al foi observada para o porta-enxerto ‘Sharpe’. 'Capdeboscq', DB-SEN-09-23, FB-ESM-09-43, JB-ESM-09-13, JAH-MAC-09-77, SAS-SAU-09-71 e VEH-GRA-09 -55 seleções de porta-enxertos são tolerantes ao Al. A utilização de variáveis fisiológicas e bioquímicas apresenta potencial para seleção de porta-enxertos clonais tolerantes ou resistentes ao Al

Adubação nitrogenada foliar e incidência da podridão parda (Monilinia fructicola) em pêssegos da cultivar 'Chimarrita'.

Suplemento. Edição dos resumos do 44º Congresso Brasileiro de Fitopatologia, 2011, Bento Gonçalves. Resumo 513

Aplicação de potássio e cálcio diminui a incidência de Monilinia fructicola em pessegueiro.

Suplemento. Edição dos resumos do 44º Congresso Brasileiro de Fitopatologia, 2011, Bento Gonçalves. Resumo 755

Aplicação foliar de cálcio e consequências na podridão parda (Monilinia fructicola) em pêssegueiros da cultivar 'Chimarrita'.

Suplemento. Edição dos resumos do 44º Congresso Brasileiro de Fitopatologia, 2011, Bento Gonçalves. Resumo 270

Boro, aplicação foliar e conseqüências na podridão parda (Monilinia fructicola) em pêssegos da cultivar 'Chimarrita'.

Suplemento. Edição dos resumos do 44º Congresso Brasileiro de Fitopatologia, 2011, Bento Gonçalves. Resumo 514

Aplicação foliar de potássio e consequências na podridão parda (Monilinia fructicola) em pêssegueiros da cultivar 'Chimarrita'.

Suplemento. Edição dos resumos do 44º Congresso Brasileiro de Fitopatologia, 2011, Bento Gonçalves. Resumo 743

Root system morphology of ipê-roxo tree grown in soil subjected to phosphorus application in subtropical climate region

Phosphorus (P) availability in subtropical soils does not often meet the nutritional demand of native tree species such as the ipê-roxo tree (Handroanthus heptaphyllus); therefore, it is necessary to supply P at planting. However, the impact of P on root system growth remains unknown. The aim of the current study was to investigate the effect of P application on root morphology of H. heptaphyllus plants over a 36-month period in a subtropical climate region. During the experiment, the plants subjected to fertilization with 40 kg P ha−1 were compared to untreated control. Plant roots were scanned through minirhizotron system 18 and 36 months after transplant (MAT), and generated images were used to determine total root length, mean root diameter and total root volume. Plant height and leaf P concentrations were also evaluated. Phosphorus application enhanced root and whole plant growth with a more evident effect at 36 MAT, when soil P availability decreased. The results give important information on the cultivation of H. heptaphyllus plants in soils presenting low P availability