Heliotropic responses of soybean cultivars at three phenological stages and under two water regimes

Pesquisa Agropecuária Brasileira

Miroslava Rakocevic²  Norman Neumaier¹  Gustavo Migliorini De Oliveira¹  Alexandre Lima Nepomuceno¹  José Renato Bouças Farias¹ 

[1] ,Instituto Agronômico do ParanáLondrina PR

关键词: Glycine max;    diaheliotropism;    irrigation;    leaf area index;    paraheliotropism;    Glycine max;    cosseno;    diaheliotropismo;    irrigação;    índice de área foliar;    paraheliotropismo;   

DOI  :  10.1590/S0100-204X2010000700005

来源: SciELO

【 摘 要 】

The objectives of this work were to determine the heliotropic movements of the upper trifoliates for two soybean cultivars, BR 16 and Embrapa 48, during a daily cycle, in three phenological stages and two water regimes, and to estimate the impact of irrigation and daily leaflet movements on agronomic characteristics and grain yield. Heliotropic movements were studied in three phenological stages: V4-V6, V7-V10, and R5 in irrigated and non-irrigated plots. For each stage, the leaflet elevation and azimuth were measured hourly. Under a low (V4-V6 stage) and mid (V7-V10 stage) leaf area index (LAI) the diaheliotropism was slightly more frequent and intensive in non-irrigated than in irrigated plants, only at early morning and late afternoon hours. At R5 stage (high LAI) the paraheliotropism of superior trifoliates was predominant and more intensive in non-irrigated plants. The heliotropic movements are correlated to carbon gain, but not to environment (light intensity or temperature), for measurements at 11h. 'Embrapa 48' expresses greater paraheliotropism than 'BR 16' at high LAI, while 'BR 16' displays lower heliotropic plasticity under irrigation. In spite of significant heliotropic differences, genotype and water availability treatments did not influence the final grain yield.

【 授权许可】

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