swollen or thickened stems) are called "heteroblastic", when they are comprised of a single node as compared to "homoblastic", when comprised of two or more nodes (Pridgeon et al., 1999).
The only direct experimental test of this notion, with "juveniles" of 4 homoblastic and heteroblastic species pairs, failed to detect an advantage of heteroblastic species (Gamage & Jesson, 2007).
One of the few exceptions is a study by Lee (1988), although he investigated the response of homoblastic species to varying light quality.
This interpretation agreed with the results of experimental work with heteroblastic Tillandsia deppeana (Adams & Martin, 1986a, b), and those of a quantitative assessment of tank water relations in two other, homoblastic species (Zotz & Thomas, 1999): the efficiency of tanks to bridge rainless periods decreases in smaller plants, suggesting that the observed morphological change represents a strategy shift from drought-tolerant "juvenile" to drought-avoiding tank form.
Noteworthy, this study was one of the few in which a homoblastic species was included to control for ontogenetic drift.
However, an experimental test with several hetero- and homoblastic species yielded no consistent support for this notion.