Uso de um mutante em auxina no estudo da desordem nutricional de nitrogênio em tomateiro
Carregando...
Data
2016-11-01
Autores
Santos, Luiz Cláudio Nascimento dos [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
A resposta do tomateiro à suficiência ou deficiência de nitrogênio depende da sinalização da auxina (AUX). O objetivo deste trabalho foi avaliar o efeito da AUX nas respostas de plantas de tomateiro à deficiência de nitrogênio (N) e sua influência na eficiência de uso de N. Foram desenvolvidos dois experimentos, o primeiro foi conduzido em câmara de crescimento, utilizando-se o mutante diageotropica (dgt) de tomateiro cultivar Micro-Tom (MT), que apresenta baixa sensibilidade à AUX. As plantas foram submetidas à ausência e à presença de N na solução nutritiva. Foram avaliados após 10 dias de omissão de N: a altura de plantas e o diâmetro do caule, massa seca da raiz e da parte aérea, comprimento, área, diâmetro e densidade da raiz, número de raízes laterais (RL), área foliar, acumulo de N e eficiência de utilização de nitrogênio (EUN) na raiz e na parte aérea, teores de clorofilas a e b, e carotenóides. O segundo experimento foi realizado na Universidad Publica de Navarra (UPNA), Espanha. Utilizou-se do delineamento inteiramente casualizado, com seis repetições, arranjados em esquema fatorial 4 x 2, correspondendo a quatro tratamentos de N (N-NO3-; N-NH4+; NO3- + AUX; omissão de N) e dois genótipos de tomateiro (MT e dgt). Foram avaliados variáveis de crescimento, fisiológicas, teores de nitrato e amônio nas folhas e raízes, proteína e glutamina sintetase (GS) nas folhas e raízes. Para todas as variáveis de crescimento, exceto diâmetro e comprimento radicular, houve efeito da interação entre os genótipos de tomateiro e tratamentos de N. Porém o diâmetro radicular apresentou redução pelos efeitos individuais dos genótipos de tomateiro e omissão e presença de N. Enquanto o comprimento radicular maior no tomateiro MT, o mutante dgt apresentou aumento no número de RL na deficiência de N. A AUX não sendo utilizada pelas plantas reduz o crescimento da parte aérea e do sistema radicular das plantas de tomateiro. O tomateiro dgt apresenta maior tolerância ao estresse por amônio, possivelmente devido ao maior acumulo desse cátion nas raízes. Além de alterações no metabolismo do N, principalmente relacionado a uma maior EUN sob deficiência de N. As respostas inéditas no desenvolvimento do dgt em condições de deficiência de N podem estar relacionadas a uma maior atividade da GS na raiz e na parte aérea nessas condições.
It has been shown that tomato response to the sufficiency or deficiency of nitrogen depends on auxin signaling (AUX). The objective of this study was to measure the effect of AUX in the responses of tomato plants to nitrogen deficiency (N) and your influence on N use efficiency. Were developed two works, where the first was developed in a growth chamber, where he was used diageotropica mutant (dgt) of tomato cultivar Micro-Tom (MT), which has low sensitivity to the AUX. The plants were subjected to the privation and the presence of N in the nutrient solution. Were evaluated after 10 days of failure N: plant height and diameter, root dry mass and shoot length, area, diameter and root density, number of lateral roots (RL), leaf area, accumulation of N and nitrogen use efficiency (NUE) in root and shoot, chlorophyll a and b levels, and carotenoids. The second experiment was carried out at the Universidad Publica de Navarra (UPNA), Spain. It was used the completely randomized design with six replications, arranged in a factorial 4 x 2, corresponding to four treatments of N (N-NO3-, N-NH4+, NO3- + AUX, omission of N) and two tomato genotypes (MT and dgt) were evaluated analyzes of growth, physiological, nitrate and Ammonium on the leaves and roots, protein and glutamine synthetase in leaves and roots. For all the growth variables except root diameter and length, there was a significant interaction between tomato genotypes and treatment N. However, the root diameter was reduced by the individual effects of tomato genotypes and omission and presence of N, while the length radicular higher in MT tomato, the dgt mutant showed an increase in the number of RL disability N. AUX not used by plants reduces the growth of shoots and roots of tomato plants. The dgt tomato has a higher tolerance to stress ammonium, possibly due to greater accumulation of this cation in the roots. As well as the dgt tomato presents changes in the N metabolism, mainly related to increased EUN under disability N. The unprecedented responses in the development of dgt N deficiency conditions may be related to increased activity of GS in the root and shoot under these conditions.
It has been shown that tomato response to the sufficiency or deficiency of nitrogen depends on auxin signaling (AUX). The objective of this study was to measure the effect of AUX in the responses of tomato plants to nitrogen deficiency (N) and your influence on N use efficiency. Were developed two works, where the first was developed in a growth chamber, where he was used diageotropica mutant (dgt) of tomato cultivar Micro-Tom (MT), which has low sensitivity to the AUX. The plants were subjected to the privation and the presence of N in the nutrient solution. Were evaluated after 10 days of failure N: plant height and diameter, root dry mass and shoot length, area, diameter and root density, number of lateral roots (RL), leaf area, accumulation of N and nitrogen use efficiency (NUE) in root and shoot, chlorophyll a and b levels, and carotenoids. The second experiment was carried out at the Universidad Publica de Navarra (UPNA), Spain. It was used the completely randomized design with six replications, arranged in a factorial 4 x 2, corresponding to four treatments of N (N-NO3-, N-NH4+, NO3- + AUX, omission of N) and two tomato genotypes (MT and dgt) were evaluated analyzes of growth, physiological, nitrate and Ammonium on the leaves and roots, protein and glutamine synthetase in leaves and roots. For all the growth variables except root diameter and length, there was a significant interaction between tomato genotypes and treatment N. However, the root diameter was reduced by the individual effects of tomato genotypes and omission and presence of N, while the length radicular higher in MT tomato, the dgt mutant showed an increase in the number of RL disability N. AUX not used by plants reduces the growth of shoots and roots of tomato plants. The dgt tomato has a higher tolerance to stress ammonium, possibly due to greater accumulation of this cation in the roots. As well as the dgt tomato presents changes in the N metabolism, mainly related to increased EUN under disability N. The unprecedented responses in the development of dgt N deficiency conditions may be related to increased activity of GS in the root and shoot under these conditions.
Descrição
Palavras-chave
Deficiência nutricional, Eficiência de utilização de nitrogênio, Fitohormônios, Nutrição mineral de plantas, Solanum lycopersicum L., Toxicidade