Other signaling hormones, such as indole-3-acetic acid (an auxin) and ethylene, appear to play a more significant role in leaf abscission.
Nitrogen (N) economy was studied by means of N productivity, N accumulation and N losses by leaf abscission.
Rapid negative change occurred in 42% of individuals, caused mostly by massive pre-flush leaf abscission (31% of all crowns).
The experiment covered the period from bud-break until leaf abscission and the experimental conditions included two irrigation and two fertilisation regimes.
This included a greater effect on stem diameter than on stem height, earlier leaf abscission, and reduced stem and leaf dry matter production at the end of the growing season.
The dormancy hormone, abscisic acid, may be concerned in this response and also in stomata closure in response to water stress and in leaf abscission (the separation of the leaf from the plant); there is a great deal of debate among scientists concerning what role, if any, this hormone plays in abscission.
Ethylene is a gaseous plant hormone and it controls the leaf number by regulating leaf abscission.
The important consequences of an SO2 enhanced g, were a reduction in WUE, which may cause earlier leaf abscission and a concomitant decline in productivity.
They showed traits such as leaf abscission during the higher stress season (November May), mucilage accumulation (in the shoot), and perennation structures that allow regrowth.
In fact, species can avoid declines in leaf water potential through leaf abscission (Hoffmann et al. 2011) and adjustments in stomatal morphology (Abrams et al. 1994).
The higher stomatal sensitivity and leaf abscission of isohydric species (A. rubrum, L. tulipifera, L. styraciflua) permitted greater safety margins, while avoiding catastrophic embolism (Hoffmann et al. 2011).
