Gaseous exchanges of corn and weeds under competition and water regimes

Claudia D M Freitas,Juliana De P Pamplona,Hamurábi A Lins,Daniel V Silva,Matheus De F Souza,Jeferson L D Dombroski

doi:10.1590/1807-1929/agriambi.v24n7p465-473

Claudia D M Freitas, Juliana De P Pamplona + Show 4 more

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https://doi.org/10.1590/1807-1929/agriambi.v24n7p465-473

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Abstract

ABSTRACT Water deficits can alter vital physiological functions and negatively affect plant growth. These effects can be intensified by weeds competing for water available to crops. The objective of this study was to evaluate the effects of competition and temporary soil water deficit on the transpiration (E), stomatal conductance (gs) and photosynthetic rate (A) of corn, Urochloa decumbens, and Bidens pilosa L. The experimental design was in randomized blocks with eight repetitions. The treatments were arranged in a 5 x 2 factorial scheme, with the first factor corresponding to the species: corn + U. decumbens, corn + B. pilosa, and corn, U. decumbens, and B. pilosa without competition. The second factor was two water regimes: daily irrigation and water restriction, which corresponded to the suspension of irrigation from the beginning of the V3 stage of corn until the time when their stomata were completely closed. The species B. pilosa and U. decumbens worsened the negative effects on E, gs, and A of corn at different intensities under water restriction. The U. decumbens was more aggressive in relation to B. pilosa while coexisting with corn in both water regimes. The competition with corn affected the E and gs of U. decumbens in the two water regimes, but the A was altered under water deficit. On the other hand, the physiological components of B. pilosa were not affected by its coexistence with corn in the two water regimes.

Highlights

IntroductionThe crop is planted in tropical, subtropical, and semi-arid regions (Cutti et al, 2016)
Corn (Zea mays L.) is one of the most produced cereals in the world
The objective of this study was to evaluate the effects of competition and temporary soil water deficit on the transpiration (E), stomatal conductance and photosynthetic rate (A) of corn, Urochloa decumbens, and Bidens pilosa L

Summary

Introduction

The crop is planted in tropical, subtropical, and semi-arid regions (Cutti et al, 2016). Stressful conditions can hamper productive stability in each region (Mickelbart et al, 2015). Abiotic stresses alter growth and development, which can reduce the productivity and quality of the harvested product (Mickelbart et al, 2015). The water deficit in the soil is one of the most relevant (Uzildaya et al, 2012). Under conditions of water restriction, plants tend to decrease stomatal conductance as a strategy to prevent water loss to the atmosphere. The complete closure of stomata prevents the entry of CO2 and, the photosynthetic rate is reduced as the severity of water stress increases (Lisar et al, 2012)

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