The Concepts of Seed Germination Rate and Germinability: A Re-Evaluation for Cool-Season Grasses

Abstract

Temperature is one the most influential environmental factors for the germination and establishment of grass species. The specific objective of this study was to determine the effects of low constant temperature on the time needed to express the full germination capacity of nondormant seedlots. Fifteen accessions, comprising seven of Lolium perenne L., three of Festuca arundinacea Schreb., three of Dactylis glomerata L. and two of Triticum aestivum L., were evaluated at constant temperatures of 5 and 21 °C. As expected, the germination rates were faster at 21 °C than at 5 °C. Indeed, at 5 °C seeds needed up to twenty-one times longer to reach the maximum germination than when tested at 21 °C. The genotypic variability found for the ratio of germination rates between the two temperatures (i.e., germination rate at 5 °C/germination rate at 21 °C) was much more variable than what is found in the literature for perennial cool-season grasses. On the other hand, in most cases, no significant differences were observed in the germinability (the capacity to germinate) response to 5 °C and 21 °C. Within the four species, twelve of the fifteen studied accessions expressed the same germinability at 5 °C and 21 °C, when given enough time. Only three accessions had final germination percentages higher at 21 °C than at 5 °C. Our results suggest that, in general, nondormant seeds at low temperatures germinate as well as nondormant seeds at near-optimal temperatures, provided they have enough time to express their germination capacity. These findings cast doubts on the validity of conclusions drawn in many studies where germination experiments were performed for a period insufficient to obtain full germination at low temperatures. Another major finding in this work concerns the risk of wrongly estimating germinability at low temperatures.

Transcriptomic Insights: Phytogenic Modulation of Buffel Grass (Cenchrus ciliaris) Seedling Emergence

“…The concentration of the phytogenic solution would have various effects on seedling growth. A low concentration of a phytogen can stimulate seedling emergence; however, the high concentration of a phytogen can inhibit it [21]. A phytogen may interact with plant hormones, including ABA and GA, to regulate seedling emergence, in which ABA is known to slow down the process but GA promotes it [22].…”

Sesame Germination Dynamics: Unravelling Sesame’s Response to Salinity and Temperature Variability

“…Additionally, 25 seeds from each treatment were evaluated for plant-related traits, including the length and dry weight of both roots and stems, after 10 days in the germinator. Furthermore, the germination rate was calculated using the following equation [14]. For salinity treatment, 2 millilitres of the prepared solutions were added to the containers containing seeds.…”

“…Success in crop production depends not only on a high seed germination rate but also on uniformity in seedling growth and the speed of plant establishment in the soil, which directly correlates with germination speed [14]. Germination speed is a crucial concept in seed structural features [20], and its assessment can be influential in predicting effective plant establishment.…”

Early Detection of Phenotypic Diversity of Alfalfa (Medicago sativa L.) in Response to Temperature

“…Unpublished data from a study on the response of alfalfa accessions to temperature during germination [ 22 ] were used to estimate germination rates ( α in % of seeds per unit of time) and the lag time between the beginning of incubation and the beginning of germination ( t c in hours). To this end, for each replicate, the cumulated number of germinated seeds was fitted to a non-rectangular hyperbole as in [ 6 , 25 ]. Maximum germination ratios ( G max , % of germinated seeds), together with α and t c at the eight germination temperatures, were used to perform a principal component analysis (PCA) [ 6 ].…”