(tldr: Why did a receptacle-stem expansion take on the role of ovary-wall expansion to attract dispersers in certain fruits like strawberries?)
The strawberry, Genus Fragaria, primarily relies on receptacle (the stem tissue) expanding to form the fleshy edible part that attracts dispersers, where dispersers (and us) consume as fleshy part is derived from receptacle. figs, pears or apples relying on Hypanthium expansion for fruit flesh acts in similar but slightly different ability of floral tissue differentiability to form fruits flesh and all of these are grouped as accessory fruits which do basal floral expansions in fruit formation.
In contrast, typical fleshy true fruits relying on ovary-wall expansion like Mango-Peach-Cherry(Drupes), Grape-tomato-currant(Berries), Pineapple where even if receptacle forms core its flesh is still from fused ovary walls. We will leave nuts and passive seed dispersal plants aside.
Now why did such receptacle-based fruits evolve across different plant families, even though this strategy looks subpar on some levels (say encoding new genes to make stem tissue take on the role for attracting) and likewise less common in plant kingdom compared to ovary-wall based dispersion-attraction fruits.
Could this be result of purely the random mutations that provided some advantage (what exactly?) in those fruit lines or was there some underlying adaptive advantage for shifts to receptacle expansions which are taking the functional role of ovary-wall expansions?
Are there any botanical literature explanations for this question. or should I settle with answer 42 and sleep peacefully.
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Edit: found these interesting related literature although not answering the above question yet:
I havenât read any literature on this, so itâs just my hypothesis, but I think in the Rosaceae one of the ancestral fruit types is a dry capsule. If plants with dry, non-animal-dispersed fruits then faced selective pressure to switch dispersal methods and get animals to eat them, you might get these weird, fleshy not -really-fruit arising.
There are many examples of tortuous developments in nature. Why do plants colorful bracts instead of colorful flowers that had invented by their ancestors?
Aside from tiny differences in the possibilities of different structures the main reason: once a feature with a function is lost the process of reinventing traits for a similar function starts more or less from a different point. There no way to remember how it once was or copy paste from other species
yes thanks, but the question is about why only the receptacle is taking the role here in certain class of fruits over other parts with those same roles. Selective pressure broadly (attracting dispersers) versus developmental blueprint choice (receptacle as fruit flesh in strawberry).
That is yes the fleshy fruits got to where they are to attract animal dispersers eventually, but within that fleshy fruits set there are various plant parts expanding after pollination with things attracting dispersers and in this example case for the strawberry that fleshy fruit is formed mainly from receptacle and not typical dominant ovary-walls strategy.
to be exact, in the paper 2 link above, there is a hypothesised ancestor to strawberry in fig 6.B.d which doesnt follow the receptacle expansion but then strawberry took on receptacle thing suddenly and not typical ovary-walls part as fruit flesh and these two strategies are kind of substitutable for same functional roles as far as I see or if I am missing something deeper in here for those fruit differences I cant figure out. In anthropocentric biased view, I like to know why exactly did strawberry chose to make me ultimately eat only its stem tissues. (ofc strawberry is cultivated, but the question is broadly same from context)
Yes, I understand a chance mutations or loss in those fruit clades could effectively co-opt other traits for catering to same end-functional pathways and evolution eventually found solutions in the strawberry here ofcourse but my question is why this particular strategy happened here. I read if things independently evolved across clades resulting in convergence functions (receptacle as major entity in some final flesh fruits) then that can point to some underlying âstartingâ developmental constraints or structural predispositions in those pathways right? As in, given the ovary-wall expansion is common in fleshy-attractive fruits, what concrete starting biases really made receptacle expansion evolutionary stable in certain fruit clades.
Are you sure that the âfleshy edible partâ in raspberries and other Rubus is receptacle tissue? as far as I can tell, only the drupes are picked then eaten, the receptacle stays attached to the bush. Or are there cultivated varieties in your part of the world where this part develops as edible?
sorry, yes I have to edit the main post fruit examples again but as in last comment and title it is about reason for strawberry receptacle factor. thanks
