Crescimento e respostas enzimáticas do feijoeiro caupi sob estresse hídrico e nematoide de galhas

Abstract

R E S U M OConsiderando a importância do feijoeiro caupi no Nordeste brasileiro, o presente estudo teve, por objetivo, avaliar o crescimento e os aspectos bioquímicos do cultivar EPACE-10 submetido a estresse hídrico e parasitismo de Meloidogyne incognita em condições de casa de vegetação. O delineamento adotado foi de blocos ao acaso em esquema fatorial 2 (com e sem nematoide) × 2 (com e sem estresse hídrico), com seis repetições. O nível de estresse hídrico aplicado (50% da capacidade do campo) diminuiu a reprodução do nematoide; entretanto, o desenvolvimento das plantas aferido pelas biomassas frescas e secas do caule e folhas, número de folhas, índice de área foliar, altura da planta e pela biomassa fresca da raiz, não foi afetado pelo estresse hídrico aplicado. As respostas das enzimas oxidativas ao estresse hídrico e parasitismo de M. incognita foram variáveis. A peroxidase não foi afetada, a catálase foi diminuída pelo parasitismo do nematoide, a ascorbato peroxidade diminuída pelo estresse hídrico e a polifenoloxidase diminuída pelo estresse hídrico e pelo parasitismo de M. incognita. Growth and enzymatic responses of cowpea under water stress and root-knot nematode A B S T R A C TConsidering the importance of cowpea beans in the Northeast of Brazil, the present study aimed to evaluate growing and biochemical aspects of cultivar EPACE-10 subjected to water stress and parasitism of Meloidogyne incognita under greenhouse conditions. The design was a randomized block design in a factorial 2 (with and without nematode) × 2 (with and without water stress), with six replications. The level of applied water stress (50% of the field capacity) reduced the nematode reproduction. However, plant growth measured by fresh and dry biomass of stems and leaves, leaf number, leaf area index, plant height and fresh root biomass was not affected by water stress applied. The responses to water stress and oxidative enzymes and parasitism of M. incognita were variable. Peroxidase was not affected; catalase was decreased by nematode parasitism, ascorbate peroxidase decreased by water stress and polyphenoloxidase decreased by water stress and parasitism of M. incognita. Palavras-chave:Vigna unguiculata Meloidogyne incognita enzimas oxidativas

Does Allium sativum L. tolerate water deficit?

“…As the water deficit increased, no significant changes were observed in the dry biomass of A. sativum organs (Table 4), with only a 40% increase in leaf biomass of plants treated with 75% CP. Some authors such as Bernier et al (2008), Morales et al (2015, Sousa et al (2015) Mendes et al (2007), Silva et al (2007) and Macêdo et al (2006) obtained similar results with those obtained in the present study. The same authors stated that water lack affects practically all physiological processes, including dry matter accumulation, which is mainly responsible for productivity, in which the most vigorous plants, when subjected to water deficit, have physiological mechanisms that allow its development even under drought conditions.…”

“…Thus, data observed in the present study corroborate data found in the literature for other plant species exposed to different levels of water deficit. (FUMIS e PEDRAS, 2002;MELO, 2012;QUEIROZ et al, 2002;SOUSA et al, 2015).…”

Physiological Responses of Physalis angulata Plants to Water Deficit

“…Sugars contents are highly sensitive to environmental stresses (Rosa et al, 2009) and their accumulation consists of a defense mechanism of the plant to dehydration, adjusting the ionic and osmotic balance and maintaining the turgor of the cells (Marijuan & Bosch, 2013 ). Organic solutes accumulation under abiotic stresses conditions has been reported in several crops, such as cowpea (Sousa et al, 2015), pigeon pea (Monteiro, Cruz, Nardin, & Santos, 2014), tomato (Ganbari & Sayyari, 2018) and citrus (Zou, Wu, Huang, Ni, & He, 2013;Vives-Peris, Candeas, & Clementes, 2017). Other adaptive responses to water deficit may occur simultaneously, as changes in gas exchange and nitrate reductase enzyme activity, limiting nitrogen assimilation (Alguacil, Caravaca, Díaz-Vivancos, Hernández, & Roldán, 2006).…”

Salicylic acid in the physiological priming of onion seeds subjected to water and salt stresses

“…Given the results, it is possible to state that onion seedlings have the accumulation of proline as a mechanism of tolerance to water stress, and this compound is used for osmotic adjustment and defense against water loss, maintaining the water potential in the leaf (Sousa et al, 2015). However, the accumulation of soluble sugars did not stand out as an effective mechanism in mitigating the effects of water stress on onion seedlings.…”

“…Thus, it can be verified that, under conditions of low water availability, there is a reduction in the initial development of onion seedlings, likely due to metabolic damage to tissues and increased respiration. The metabolic changes include peroxidases, protein denaturation and increase in the levels of amino acids, especially proline (Sousa et al, 2015).…”