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Uso de fenotipagem digital na avaliação do efeito de bioestimulantes na tolerância da cultura do milho ao défice hídrico
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Abstract(s)
Atualmente, as alterações climáticas têm vindo a representar uma escassez dos
recursos hídricos e um crescente aumento das temperaturas. Associado a este cenário de seca
prolongada e tendo em consideração que a cultura do milho apresenta uma considerável
necessidade hídrica e um grande interesse económico, torna-se importante realizar estudos
relacionados com o défice hídrico de forma a evitar que a sua produtividade seja afetada.
Como tal, o presente estudo teve como objetivo principal avaliar o efeito do uso de
bioestimulantes microbianos no aumento da tolerância ao stress hídrico induzido por défice
hídrico, na cultura do milho, através da monitorização por fenotipagem digital de alto
rendimento.
Na primeira fase do estudo, foram avaliadas dez estirpes de bactérias com efeito
bioestimulante, perante duas modalidades hídricas: sem restrições hídricas (SRH) e com
restrições hídricas (CRH). Procedeu-se à seleção de três bioestimulantes que mostraram uma
maior indução de tolerância ao défice hídrico, através da medição da biomassa final das
plantas. Como tal, observou-se que os tratamentos Bio 2, Bio 5 e Bio 10, na modalidade
SRH comprovaram o seu efeito bioestimulante comparativamente ao Controlo; na
modalidade CRH, induziram os maiores aumentos de biomassa de 24%, 41% e 21%,
respetivamente, comparando com as plantas Controlo. Como tal, selecionaram-se estes
tratamentos para a fase seguinte.
Na fase posterior, realizou-se um estudo comparativo entre as três estirpes de
bactérias selecionadas, utilizando-se as mesmas modalidades hídricas. O acompanhamento
do estudo através da fenotipagem digital de alto rendimento e as medidas finais efetuadas,
permitiram obter resultados que demonstraram que a redução de água influenciou
negativamente o desenvolvimento das plantas do Controlo na modalidade CRH, em
comparação com as plantas do Controlo na modalidade SRH. Quanto à ação dos
bioestimulantes, as plantas em conforto hídrico não só apresentaram um desenvolvimento
superior, como também mostraram valores fisiológicos superiores aos do Controlo na mesma
modalidade hídrica. Nas plantas da modalidade CRH, os bioestimulantes mitigaram a
interrupção do crescimento, promovendo o desenvolvimento contínuo, por vezes
equiparando-se às plantas do Controlo em condições hídricas favoráveis. Embora, nem todos
os parâmetros fisiológicos tenham aumentado significativamente, os resultados da aplicaçãoIV
dos bioestimulantes foram consistentemente superiores aos do Controlo, nas mesmas
condições hídricas.
Ainda nesta última fase, o tratamento Bio 5 apresentou, maioritariamente, os
melhores resultados tanto morfologicamente como fisiologicamente, seguido pelo
tratamento Bio 10 e, por fim, o tratamento Bio 2; todos superando o Controlo em ambas as
modalidades hídricas.
Currently, climate change has led to a scarcity of water resources and a rising increase in temperatures. In this scenario of prolonged drought, considering that maize crop has high water needs and substantial economic interest, it becomes crucial to conduct studies concerning to water deficit irrigation to prevent its productivity from being affected. Thus, the main objective of this study was to evaluate through high-troughput digital phenotyping the effect of using microbial biostimulants in increasing plant tolerance to water stress. In the first phase of this study, ten strains of bacteria with biostimulant effects were evaluated under two water regimes: without water restrictions (SRH) and with water restrictions (CRH). Three biostimulants that induced the highest plant tolerance to water stress were selected by the final biomass of the plants. It was observed that treatments Bio 2, Bio 5, and Bio 10 under SRH confirmed their biostimulant effect compared to the Control. Under CRH, these treatments also induced the highest biomass increment respectively 24%, 41%, and 21%, compared to the Control plants. Therefore, these treatments were selected for the next research phase. In the subsequent phase, a comparative study was conducted among the three selected bacterial strains, using the same previous water regimes. Monitoring the tested maize plants through high-throughput digital phenotyping and final measurements (as biomass, Fv/Fm and plant nutrition) demonstrated that 50% of water reduction affect negatively plant growth, as observed in Control plants under CRH compared to Control plants under SRH. Regarding the action of the biostimulants, the plants without water restriction not only showed superior growth but also presented superior to the Control under the same water regime. In CRH plants, biostimulants mitigated growth interruption, promoting continuous development, sometimes similarly to Control plants no water restrictions. Although not all physiological parameters were significant higher then the Control plants with no water restriction, the results of biostimulant application were consistently superior to the Control under the same water conditions. In this final phase, the Bio 5 treatment presented the best results both morphologically and physiologically, followed by Bio 10, and finally Bio 2; all surpassing the Control in both water regimes.
Currently, climate change has led to a scarcity of water resources and a rising increase in temperatures. In this scenario of prolonged drought, considering that maize crop has high water needs and substantial economic interest, it becomes crucial to conduct studies concerning to water deficit irrigation to prevent its productivity from being affected. Thus, the main objective of this study was to evaluate through high-troughput digital phenotyping the effect of using microbial biostimulants in increasing plant tolerance to water stress. In the first phase of this study, ten strains of bacteria with biostimulant effects were evaluated under two water regimes: without water restrictions (SRH) and with water restrictions (CRH). Three biostimulants that induced the highest plant tolerance to water stress were selected by the final biomass of the plants. It was observed that treatments Bio 2, Bio 5, and Bio 10 under SRH confirmed their biostimulant effect compared to the Control. Under CRH, these treatments also induced the highest biomass increment respectively 24%, 41%, and 21%, compared to the Control plants. Therefore, these treatments were selected for the next research phase. In the subsequent phase, a comparative study was conducted among the three selected bacterial strains, using the same previous water regimes. Monitoring the tested maize plants through high-throughput digital phenotyping and final measurements (as biomass, Fv/Fm and plant nutrition) demonstrated that 50% of water reduction affect negatively plant growth, as observed in Control plants under CRH compared to Control plants under SRH. Regarding the action of the biostimulants, the plants without water restriction not only showed superior growth but also presented superior to the Control under the same water regime. In CRH plants, biostimulants mitigated growth interruption, promoting continuous development, sometimes similarly to Control plants no water restrictions. Although not all physiological parameters were significant higher then the Control plants with no water restriction, the results of biostimulant application were consistently superior to the Control under the same water conditions. In this final phase, the Bio 5 treatment presented the best results both morphologically and physiologically, followed by Bio 10, and finally Bio 2; all surpassing the Control in both water regimes.
Description
Dissertação, Mestrado, Engenharia Agronómica, Instituto Politécnico de Santarém, Escola Superior Agrária, 2024
Keywords
milho défice hídrico bioestimulante fenotipagem digital de alto rendimento. maize water deficit
Citation
Carvalho, C. A. (2024). Uso de fenotipagem digital na avaliação do efeito de bioestimulantes na tolerância da cultura do milho ao défice hídrico. Dissertação de Mestrado na área da Engenharia Agronómica, apresentada na Escola Superior Agrária de Santarém. http://hdl.handle.net/10400.15/4965