Abstract
Background:
Substantial losses to crops can occur due to the presence of sourgrass in agroecosystems, which is promoted by its seed dispersal ability. Environmental factors can affect sourgrass germination and emergence.
Objective:
The objective of this study was to determine the effects of water restriction, salinity, and depth of sowing on the sourgrass germination and emergence processes.
Methods:
Experiments using sourgrass seeds were conducted under controlled conditions simulating osmotic and saline stress and seeding depths. The data collected was submitted to analysis of variance and adjusted to models by regression analysis.
Results:
Smaller osmotic potentials reduced germination, normal seedlings, and increased quiescence, with no germination occurring from -0.80 MPa. Salinity caused a decrease in germination from 20 mM NaCl, influencing the percentage of normal and abnormal seedlings and quiescent seeds. Seed depth influenced the emergence of seedlings, with the maximum percentage of emergence (83%) in the seeds placed on the substrate surface. The maximum depth from which sourgrass seedlings emerged was 7.6 cm.
Conclusions:
The results lead to the conclusion that the sourgrass germination process tolerates low osmotic potentials and salinity levels. Despite being small sized seeds, they can emerge from high depths. These characteristics justify its occurrence in several regions and agroecosystems, especially in perennial and no-till crops lacking soil cover.
Keywords:
Digitaria insularis
; water stress; seeding depth
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The dots represent the means of the treatments and the bar the corresponding standard error.
The dashed line identified by D50 corresponds to the osmotic potential associated with half of the maximum germination speed coefficient.
The dashed line identified by MAX corresponds to the osmotic potential associated with the maximum germination synchronization index.
The dashed line identified by D50 corresponds to the osmotic potential associated with half of the maximum normal plant reduction. The dots represent the means of the treatments and the bar the corresponding standard error.
The dashed line identified by D50 corresponds to the osmotic potential associated with half of the maximum non-quiescent seeds. The dots represent the means of the treatments and the bar the corresponding standard error.
The dots represent the means of the treatments and the bar the corresponding standard error.
The dashed line identified by D50 corresponds to salinity associated with half of the maximum germination speed coefficient.
The dashed line identified by MAX corresponds to the salinity associated with the highest seed germination synchronization index.
The dashed line identified by D50 corresponds to the osmotic potential associated with half of the maximum percentage of normal plants. The dots represent the means of the treatments and the bar the corresponding standard error.
The dashed line identified by D50 corresponds to the osmotic potential associated with half of the maximum percentage of non-quiescent seeds. The dots represent the means of the treatments and the bar the corresponding standard error.
The dashed line identified by D50 corresponds to the depth associated with half of the maximum emergence reduction. The dots represent the means of the treatments and the bar the corresponding standard error.