Interaction Effects of Seed Mass and Temperature on Germination in Australian Species of Frankenia (Frankeniaceae)

Abstract

The seed size and number theories have been proposed to explain the advantages of having many small versus a few large seeds in plants. In particular, seed germination is predicted to be shaped by temperature, and may differ for small and large seeds. In this study, we experimentally test germination at different temperatures in 12 species of arid zone plants in the genus Frankenia L. that differ in seed mass. Seed mass was categorized as "smaller-seeded species" versus "larger-seeded species" for analysis (six species per category). Many of these species co-occur geographically and hence experience similar abiotic conditions (unpredictable rainfall, extremes in temperature, poor soil conditions). The results demonstrated differences in germination as a result of the temperature*seed mass(species) interaction effect. There were significant differences in germination rates across seed mass categories during the first eight days of germination. Germination rates were higher in the larger-seeded species than the smaller-seeded species. Smaller-seeded species had lower germination success but had higher germination rates at lower temperatures, and had a more stringent temperature as a germination cue. These findings are discussed in the context of lifehistory strategies in arid zone plants.

Seed germination responses to seasonal temperature and drought stress are species‐specific but not related to seed size in a desert steppe: Implications for effect of climate change on community structure

“…The nonsignificant relationship between seed size and mean germination percentage at different temperature/water stress conditions in our study suggests that regardless of their seed size most species in the desert steppe have the ability to germinate under low temperature and drought stress in the early season, which would increase plant fitness by increasing growing time. Our results do not support the general assumption that large‐seeded species necessarily germinate to higher percentages than small‐seeded species (Easton & Kleindorfer, ; Grime et al, ; Norden et al, ; Rees, ; Venable & Brown, ). However, our results are consistent with those of a study of 1795 species at the global scale reporting that the distributions of seed mass of species with dormant and nondormant seeds strongly overlaps (Jurado & Flores, ).…”

Correspondence of seed traits with niche position in glacier foreland succession

“…Seed mass did not correspond with T opt for the investigated species nor did seed mass explain the suitable temperature range for germination. This result contradicts the findings of Easton and Kleindorfer (2008), who found significant interaction effects of seed mass and temperature responses across several species within a single genus. In contrast, all the investigated species in our study belonged to different genera from eight different families.…”

“…Theoretically, imbibition and germination rate of seeds, both temperature dependent, are suggested to be higher in smaller seeds (Easton and Kleindorfer 2008;Leishman et al 2000). However, we are not aware of any study that has investigated the role of both the seed mass and temperature requirements for germination of species along primary successional gradients.…”

Differences in the sexual aposymbiotic phase of the reproductive cycles of Parmelina carporrhizans and P. quercina. Possible implications for their reproductive biology

“…However, variation in seed size persists, despite the apparent advantages of being large-seeded (Westoby et al 2002). Easton & Kleindorfer (2008 b ), using Frankenia L. species as a model, concluded that smaller-seeded species had lower germination success at medium and high temperatures but greater success at low temperatures. Furthermore, these species delay germination until they have experienced several days of soil-water contact.…”