Effects of bird ingestion on seed germination of Sorbus commixta

Abstract

To determine the effects of ingestion by birds on seed germination, we performed germination experiments in the field and laboratory with Sorbus commixta. The germination of four groups of seeds was compared: ingested seeds, seeds defecated in feces after feeding of fruits to birds; extracted seeds, seeds deliberately extracted from the fruit pulp; juiced seeds, seeds plus the juice of the pulp after seeds had been deliberately extracted from the pulp; intact seeds, seeds in untreated intact fruits. In the laboratory, intact and juiced seeds hardly germinated, but ingested and extracted seeds germinated. Thus, the pulp and its juice appeared to inhibit germination, but seeds could germinate without ingestion by birds once the seeds had been manually extracted from the pulp. In the field, intact fruits did not germinate in the first spring, because the seed was still covered with pulp. The pulp of intact seeds decomposed during the first summer, and thus, the seeds had the potential to germinate during the second spring. In fact, most intact seeds do not germinate during the second spring either, since they lose their viability during the first summer. Thus, under natural conditions, most seeds of Sorbus commixta cannot germinate without bird ingestion.

Key factors affecting seed germination of Copaifera langsdorffii, a Neotropical tree

“…Biotic factors, intrinsic to the seed and/or interactions with other organisms and abiotic factors, such as light, temperature, humidity and fire, affect germination differently (Baskin & Baskin 1998). Zoochorous seeds have fleshy structures that attract and reward their dispersers (Christianini et al 2007) and often have substances that inhibit germination (Cipollini & Levey 1997;Yagihashi & Miyamoto 1998;Robertson et al 2006). Thus, in addition to transporting seeds away from the mother plant, seed dispersers can be important to the successful germination of some species by removing compounds that inhibit germination (Robertson et al 2006;Silveira et al 2012;Lessa et al 2013).…”

Genetic variability of a scattered temperate forest tree: Sorbus torminalis L. (Crantz)

“…This species is insect pollinated and the seeds are dispersed by birds. A recent study on Sorbus commixta in Japan [45] reports that extraction of seeds from the pulp is necessary for their germination. Sorbus torminalis is also able to propagate asexually through the production of suckers.…”

Relationships Between the Fruiting Phenology of Prunus jamasakura and Timing of Visits by Mammals - Estimation of the Feeding Period Using Camera Traps

“…The fruits are readily eaten by numerous birds and mammals (Koike & Masaki, 2008;Yoshikawa et al, 2009;Tsuji et al, 2011b), which digest the fruit flesh and disperse the seeds in their droppings. Some rodents and a few birds (notably the Streptopelia orienta, Eastern turtle dove) also crack open the stones to eat the kernel (Yagihashi, 2001;Koike, unpublished data).…”