Physiological and oxidative stress responses of four potato clones to aluminum in nutrient solution

Abstract

Aluminum toxicity is a serious problem in Brazilian soils and selecting potato clones is an important strategy to produce this crop on these kinds of soils. Potato clones, Macaca, SMIC148-A, Dakota Rose, and Solanum microdontum, were grown in a nutrient solution (pH 4.0) with 0, 50, 100, 150 and 200 mg Al L -1 . After 7 d, Al concentration in both root system and shoot of all clones increased linearly with increasing Al levels. Based on relative root growth, S. microdontum and SMIC148-A were considered Al-tolerant clones, whereas Macaca and Dakota Rose were considered Al-sensitive. Shoot growth in Macaca linearly decreased with increasing Al levels. Root H 2 O 2 concentration in both Al-sensitive clones increased with increasing Al supply, whereas in Al-tolerant clones it either decreased (SMIC148-A) or demonstrated no alteration (S. microdontum). Shoot H 2 O 2 concentration increased linearly in Macaca, whereas for Dakota Rose it showed a quadratic relationship with Al levels. On the other hand, shoot H 2 O 2 concentration in the Al-tolerant clones either demonstrated no alteration (S. microdontum) or presented lower levels (SMIC148-A). Root catalase (CAT) activity in both Al-sensitive clones increased with increasing Al levels, whereas in Al-tolerant clones it either demonstrated no alteration (SMIC148-A) or presented lower levels (S. microdontum). Shoot CAT activity in the S. microdontum increased curvilinearly with increasing Al levels. In all potato clones, chlorophyll concentration showed a curvilinear response to Al supply, where in Al-sensitive clones it decreased upon addition of Al exceeding 100 mg L -1 , but in SMIC148-A it increased at levels between approximately 100 and 150 mg L -1 , and decreased in S. microdontum regardless of the Al level. Carotenoid concentrations in the Al-sensitive clones were linearly decreased with increasing Al levels. Aluminum supply caused root lipid peroxidation only in the Al-sensitive clones, whereas in the shoot it increased linearly in the Al-sensitive clones and in S. microdontum it only increased at around 50 mg L -1 . Most of root protein oxidation was only observed in the Al-sensitive clones. However, shoot protein oxidation was increased with increasing Al levels for all potato clones. These results indicate that oxidative stress caused by Al in potato may harm several components of the cell, mainly in Al-sensitive clones. Keywords: aluminum toxicity, antioxidative enzymes, growth, oxidative stress, Solanum tuberosum Respostas fisiológicas e de estresse oxidativo de quarto clones de batata ao alumínio em solução nutritiva: A toxicidade do alumínio é um problema sério em solos brasileiros e a seleção de clones de batata é uma estratégia importante para produzir essa cultura em tais solos.

Emergência de plântulas e crescimento inicial do pinhão manso exposto a alumínio

“…Normalmente, plantas intoxicadas pelo alumínio apresentam sintomas de deficiência de nutrientes, tais como fósforo, cálcio, magnésio, potássio e molibdênio, devido a diminuição da capacidade de absorção, transporte e uso destes nutrientes (TABALDI et al, 2007). Peixoto, Pimenta e Cambraia (2007), observaram coloração amarelada nas folhas de plantas de sorgo tratadas com alumínio, além de tonalidades arroxeadas, principalmente nas bainhas e nas margens do limbo, caracterizando sintomas da deficiência de fósforo.…”

“…Quando são submetidas a adição de alumínio os sintomas são observados rapidamente, principalmente pela ocorrência de necrose nas folhas (MARIN et al, 2004;TABALDI et al, 2007;MACEDO et al, 2008). Entretanto, em decorrência da sua complexidade química, a fitotoxicidade do alumínio não está totalmente esclarecida.…”

“…No entanto, a tolerância genética ao alumínio varia entre espécies e indivíduos de uma mesma espécie (TABALDI et al, 2007).…”

Aluminum stress in Crambe abyssinica Hochst

“…As result of the limited growth of the radicles, water absorption and nutrient uptake, transport and utilization are severely impaired. Thereby, several plant species decreased production of biomass when exposed to aluminum toxicity (Tabaldi et al, 2007).…”

Atividade relativa da catalase de losna-branca (Parthenium hysterophorus) comparada à de outras espécies daninhas

“…As catalases são um grupo de enzimas que promove a degradação de duas moléculas de peróxido de hidrogênio (água oxigenada) em água e oxigênio (Chelikani et al, 2004;Tabaldi et al, 2007). Assim, maiores concentrações de catalase nas células, ou mesmo maior atividade dessa enzima, podem ser explicações para a tolerância da losna-branca ao herbicida paraquat.…”