Environmental maternal effects on temperature-dependent dormancy release in Polygonum aviculare buried seeds

DIEGO BATLLA; BENECH-ARNOLD, ROBERTO; ROCIO BELÉN FERNANDEZ

Caete

Congreso; V Conference of Seed Ecology; 2016

For many species, timing and extent of seedling emergence are strictly related to the dormancy state of the seed-bank. As several weed seed populations show dormancy, the possibility of predicting their emergence in the field depends largely on our knowledge of seed dormancy dynamics in relation to environmental factors. Although post-shedding regulation of dormancy has been widely studied and modeled, there is scarce information related to maternal effects on seed-banks dormancy behavior and almost no attempt to include these effects on predictive models of seedling emergence. In this work, we studied the effects of (i) flowering-time (which define seed-development and maturation environment), (ii) photoperiod during seed-development and maturation, and (iii) dispersal-time, on dormancy release of Polygonum aviculare seeds. To study the influence of (i), we carried out plantings under field conditions in contrasting dates. To study (ii), plants were grown under natural and extended (+4hs) photoperiod conditions. Finally, to analyze (iii), we performed successive harvests of mature seeds. Collected seeds (from experiments i, ii and iii) were buried in pots and stored at 1.6, 5 and 9.8°C. At different times during storage, seeds were exhumed and germination was tested at 10, 15, 20 and 25ºC. Based on obtained germination time-course curves, we established changes in the permissive thermal range for seed germination through variations in the limit temperatures using a mathematical germination model. We found that dormancy release and, hence, germination patterns were significantly affected by seed maturation conditions. An increase in dormancy loss rate related to a faster decrease of the lower limit temperature for germination with delay in planting date was observed. Maternal photoperiod conditions could explain, at least partially, these differences. Mathematical models for dormancy loss which include the effect of maternal environment were developed and simulations of emergence patterns in the field were performed.