Poster: Ecophysiology

Abs # 42: Salinity and herbivory induction of jasmonic and salicylic acid in leaves and flowers of Iris hexagona

Presenter:	Mopper, Susan , mop@louisiana.edu
Authors	Mopper, Susan  (A)   Wang, Yongyin  (B)   Hasenstein, Karl  (A)
Affiliations:	(A): University of Louisiana (B): Mount Sinai Medical Center
Web Site:	http://www.ucs.louisiana.edu/~sxm1886/

The plant signaling hormones jasmonic acid (JA) and salicylic acid (SA) are crucial to many physiological processes and initiate systemic responses to abiotic and biotic stress. Disentangling their ecological roles is a daunting challenge because of the complexity of their separate and interactive activity and the potential for positive and negative crosstalk between them. Our research compares the effects of experimental salinity and leafmining insects on phytohormone induction in a native iris. Both salinity and herbivory upregulated JA and down-regulated SA in foliage, but salinity produced a stronger effect. Leafminers suffered greater mortality on salt-stressed plants, despite elevated leaf nitrogen. Floral induction patterns differed substantially from foliage. Salinity increased floral SA by 30% and had no effect on floral JA. We conclude that 1) patterns of induction vary markedly in different plant tissues, and 2) salinity stress elicits stronger hormonal responses herbivory. This research was supported by National Science Foundation grant DEB-0124901.