Seeds integrate biological information about conspecific and allospecific neighbours

Abstract

Numerous organisms integrate information from multiple sources and express adaptive behaviours, but how they do so at different developmental stages remains to be identified. Seeds, which are the embryonic stage of plants, need to make decisions about the timing of emergence in response to environmental cues related to survival. We investigated the timing of emergence of (Plantaginaceae) seed while manipulating the presence of seed and the relatedness of neighbouring seed. The relatedness of neighbouring seed and the presence of seeds of did not on their own influence the timing of emergence. However, when encountering a seed, a seed emerged faster in the presence of a sibling seed than in the presence of a non-sibling seed. Water extracts of seeds gave the same result. We show that seeds integrate information about the relatedness of neighbouring seeds and the presence of seeds of a different species via water-soluble chemicals and adjust their emergence behaviour in response. These findings suggest the presence of kin-dependent interspecific interactions.

Kin discrimination allows plants to modify investment towards pollinator attraction

“…The greater advertising effort of focal plants growing with kin than with non-kin is hard to explain without invoking kin selection. Kin selection has been invoked to account for resource allocation linked to plant competitive ability, including root growth 27 , 38 , 40 and the timing of seedling emergence 31 . The interpretation of some of these studies has been questioned, because a greater mean competitiveness of unrelated individuals may simply reflect either a greater variance in competitiveness (as a consequence of Jensen’s inequality 41 ), or the possibility that non-kin groups comprise one or more particularly competitive individuals 42 , 43 .…”

“…Arabidopsis thaliana also responded to the identity of neighbours by increasing lateral root growth in the presence of root exudates from non-kin plants compared with kin 28 . Even seed emergence time, a trait with important effects on competitive ability 29 , 30 , has been found to vary as a function of the relatedness of neighbouring seeds: in Plantago asiatica , seeds accelerated their emergence in the presence of a competing species only if accompanied by kin 31 . Whereas all these examples involve responses to the context of resource competition, we ought to expect reproductive traits such as floral display similarly to depend on neighbour relatedness.…”

Influence of hairy vetch seed germination and maturation on weediness in subsequent crops

“…The method of scattering seed into the boxes could have encouraged faster germination because the seed could have been very close to one another. Studies have shown that germination can occur more quickly when exposed to competition from seeds of the same species but the overall amount of germination is not affected (Orrock & Christopher, ; Yamawo & Mukai, ). However, our methods mimicked drilling or aerial seeding, which are popular methods of seeding and neither provides precise placement of seed.…”

Influential neighbours: Seeds of dominant species affect the germination of common grassland species

“…Therefore, the ability of a seed to assess whether the current environment is appropriate for establishment and for subsequent growth is expected to be under strong selective pressure (Hierro et al, 2009; Renne et al, 2014). Indeed, the environmental cueing mechanism of seeds is so fine‐tuned that not only the abiotic environment or adult plants, but even the neighbouring seeds or young seedlings can significantly affect germination (Dyer et al, 2000; Lortie and Turkington, 2002; Tielbörger and Prasse, 2009; Orrock and Christopher, 2010; Fenesi et al, 2014; Renne et al, 2014; Yamawo and Mukai, 2017). These small‐scale seed–seed interactions might have a decisive role in the dynamics of plant populations (e.g.…”

“…sugars, phenolics, antifungals, see Bais et al, 2004). Moreover, there is mounting evidence that seeds of certain species assess the presence of other plants and modulate their germination according to the species‐specific biotic signals (Dyer et al, 2000; Renne et al, 2004; Tielbörger and Prasse, 2009; Orrock and Christopher, 2010; Renne et al, 2014; Yamawo and Mukai, 2017). These species‐specific effects can be due to phytochemicals released from the seed coat, and later to changes in soil chemistry related to root or shoot growth (Renne et al, 2004; Tielbörger and Prasse, 2009).…”