No abstract

Lateral root emission contributes to the mechanism of drought escape in Catetão. Catetão increased the root number at 60-90° angle under drought stress. Membrane integrity was less compromised during drought stress in Catetão. Ratio of deep rooting can be used to select tolerant genotypes to the drought stress.

No abstract

Todo o conteúdo deste livro está licenciado sob uma Licença de Atribuição Creative Commons. Atribuição 4.0 Internacional (CC BY 4.0).O conteúdo dos artigos e seus dados em sua forma, correção e confiabilidade são de responsabilidade exclusiva dos autores. Permitido o download da obra e o compartilhamento desde que sejam atribuídos créditos aos autores, mas sem a possibilidade de alterá-la de nenhuma forma ou utilizá-la para fins comerciais.

RESUMO:Reduzir as quantidades de fertilizantes nitrogenados e encontrar cultivares com maior eficiência no uso de nitrogênio são os principais objetivos atualmente da nutrição de plantas, pois parte do nitrogênio (N) aplicado ao solo com o intuito de maximizar a produção, pode ser perdido por lixiviação para o lençol freático, lagos e rios ou para a atmosfera causando graves problemas ambientais e aumento no custo de produção. Dentre as estratégias para aumentar a eficiência de uso de N é proposto no presente trabalho superexpressar o transportador de nitrato OsNPF4.11 em arroz. As linhagem transformadas OsNPF4.11 foram cultivadas em solução nutritiva contendo 0,2 mM N-NO 3 -. Foi observado que as plantas transgênicas apresentaram um maior acúmulo de NO 3 -na raiz o que afetou o crescimento das plantas, as quais apresentaram uma menor massa seca de parte aérea e um sistema radicular menos desenvolvido.Palavras-chave: eficiência de uso; nitrogênio; Oryza sativa L. Overexpression of nitrate transporter OsNPF4.11 (OsNRT1.2) affects growth in rice plantsABSTRACT: Reduce the amounts of nitrogen fertilizers and finding varieties with a high nitrogen use efficiency are the main objectives of plant nutrition. A large part of the nitrogen (N) applied to the soil in order to maximize production is lost by leaching to the groundwater, lakes and rivers or to atmosphere by volatilization causing serious environmental impacts and and high production costs. Among the strategies to increase NUE in the present work we propose to overexpression the nitrate transporter OsNPF4.11 in rice. Transformed OsNPF4.11 lines were grown in nutrient solution containing 0.2 mM N-NO 3 -. It was observed that the transgenic plants had a greater NO 3 -accumulation in the root affecting the plants growth, which presented a lower shoot dry mass and a less developed root system.

Purpose The expression patterns of the NRT2 genes have been well described, however, it is not well known the role of OsNRT2.4 in root growth. In this study we thus aimed at investigating the role of high-affinity NO3- transport OsNRT2.4 in NO3--regulated and the modulation of root growth.Methods Through the gene silencing technique amiRNA-mediated we successfully obtained osnrt2.4 knockdown lines to study the role of OsNRT2.4 on root growth under low nitrate conditions. We performed real time RT-PCR analysis to investigate the relative gene expression level in root and shoot, soluble metabolites, and measurement of root system.Results Knockdown of OsNRT2.4 did not affect rice growth. In comparison with wild-type (WT) plants showed that knockdown of OsNRT2.4 inhibited root formation under low NO3- supply. We demonstrated that the mutant lines had significantly increased NO3- uptake than WT plants when growth in different nitrate supply; osnrt2.4 knockdown lines showed an alteration in nitrogen metabolism, and this affected the root growth. The downregulation of OsNRT2.4 enhanced the expression of genes response of low external NO3- concentrations.Conclusion Herein we provide new insights in OsNRT2.4 functions. Our data demonstrated that OsNRT2.4 plays a role in root growth, nitrogen metabolic pathway and probably have functions in nitrate transport from root to shoot under low nitrate availability in rice.