The Changing Concept of Auxin

Apical organization and differential growth in ferns

“…In particular, the subapical region emerges as one which shows great plasticity under the impact of factors of very different kinds. It is, of course, tempting at this point to consider how some of the developments in the subapical region might be interpreted in terms of auxin, auxin-gibberellin, or auxin-kinin activities, as recently discussed by Kefford & Goldacre (1961, where the relevant literature is cited), but what is really needed is a new accession of fact. Recent experimental work indicates that this may well be possible.…”

Growth substance sensitivity: The limiting factor in plant development

“…nitrate, phosphate, calcium) water (drought or flooding), photoperiods and general light availability (shading), sugar, temperature, osmotic pressure (salinity), and other numerous unrelated chemicals including growth substances (Trewavas 1979a(Trewavas , 1981a as well as genetic and other biotic factors. The same is similarly true of cambial development (Philips 1976), cell extension (Kefford and Goldacre 1961),, seed germination (Taylorson and Hendricks 1977), flowering (Chailakhyan 1968), dormancy induction (Nooden and Weber 1978), abscissioti (Addicott andLynch 1955, Addicott 1970), root formation (Hartmann and Kester 1961), and almost all other aspects of plant developtnent.…”

How do plant growth substances work?

“…When the vascular tissue is cut this flow is interrupted. These materials will not only be sugars and amino acids, but other ions and chemicals known to affect coleoptile growth and listed by Kefford & Goldacre (1961). It is not too surprising that the vascular tissue is necessary to supply the apical region with nutrients; the rate of diffusion of materials from the endosperm is too slow to maintain and supply the upper rapidly-growing parts.…”