Noticed the phenomenon in atleast onions and garlic if not more; when left alone for enough time in the kitchen cupboard the onion continues to sprout forth from within itself a light-green center outgrowth.
See שביעית ו ג where the Mishna recognizes this phenomenon and distinguishes between these kind of light-green, "masturbatory" sprouts and strong, darkish-colored sprouts which result from having received external energies e.g. soil, rainwater.
בצלים שירדו עליהם גשמים וצמחו--אם היו העלין שלהן שחורים, אסורים; הוריקו, הרי אלו מותרין.
The way I see it, in the absence of ideally being able to receive its energies externally, the organism nonetheless seeks to tap into a release of it's energies from within. [Note also that the production of the light green shoots are, if I'm not mistaken, "weaker" and empirically contain less nutrients than those of the dark-green shoots, but it remains a "giving forth of energies" nonetheless...]
I would be very interested to know, scientifically, what in fact are the onions/garlics sacrificing internally that allows them to perform this "growth from within"... there must be some trade off...
And see Zohar Teruma 166b:
האי אור זרע ליה קב"ה בגנתא דעדנוי...ואי תימא בזמנא דגלותא כתיב אזלו מים מני ים....ואי תימא דאינון תולדין ואיבין הוו כמו דהוה בזמנא דגננא תמן, לאו הכי, אבל לא אתמנע זרוע דא לעלמין עיי"ש
[Addendum: not certain of the scientific validity but found discussion atleast that in humans increased masturbation causes increase of body's osteoclasts which break down bone... is there a plant equivalent to the human bone?... צע"ע]
[ועיין שער מאמרי רז"ל - מסכת בבא קמא - מאמר א' ]
