FLORAL DAMAGE INDUCES RESISTANCE TO FLORIVORY IN Impatiens capensisJournal: Arthropod-Plant Interactions
Matthew David Hank Boyer, Nicole L. SoperGorden, Nicholas A. Barber, and Lynn S. Adler*
* Corresponding author: ; Dept. of Biology, University of Massachusetts at Amherst
Online Resource 1: A study of vasculature mapping in Impatiens capensis.
To map out which branches are directly connected by vasculature in Impatiens capensis, we adapted methods of determining plant architecture from Orians et al. (2000)and Viswanathan and Thaler (2004). Plants were obtained and grown using the same methods as those in the main project, except that plants were transplanted into larger (12.7 cm) pots on 22 June 2010 and were fertilized twice (15 and 22 June 2010) with 8 granules of Osmocote classic controlled release fertilizer (NPK 14-14-14; The Scotts Company, Maryville, OH). On 30 June 2010, one fully expanded leaf was removed from each of 20 plants by cutting the petiole with a sharp razor under water. The cut petiole was then inserted in a water pick with 0.25% Rhodamine-B dye. Petioles were allowed to take up dye for 24 hours, at which time leaves above or below the site of dye introduction were visually checked for dye, and the angle each leaf differed from the dye site (with the dye site scored as 0°; total range of 0°-180°) was measured (Figure S1).
Dye traveled farther up the plant’s stem than down it, averaging 4 nodes (~10 cm) above and 1.5 nodes (~3.5 cm) below the dye site. Leaves on the same branch as the dye site always showed substantial amounts of dye in their vasculature, while leaves at the same node but on the opposite branch never showed dye in their vasculature (Figure S2). This indicates that leaves on the same branch are connected with one another via their vasculature, while leaves on opposite branches on the stem are not directly connected. Therefore, there seems to be strong vertical but not horizontal vascular connections.
There was a strong negative correlation between the angle of leaves and amount of dye (correlation: r = -0.83, r2 = 0.69, P < 0.0001), such that leaves that were approximately 50° or less away from the dye site had dye in their vasculature, while those more than 50° away did not have dye (Figure S2). Additionally, while those leaves at an angle of 10° or less showed dye throughout their entire vasculature more than 80% of the time, leaves that were at an angle of 10° to 50°only had dye throughout their entire vasculature in 5% of cases. Instead, leaves between 10° to 50° showed dye in only one half of their vasculature(on the side of the leaf closest to the dye site; 65% of the time) or didn’t have any dye at all (30% of the time; Figure S2).
Also, leaves below the dye site, regardless of angle, varied in dye presence(Figure S2). Leaves within 50° of the dye site and within the first two nodes had a 100% chance of dye in leaves above the dye site but only a 67% chance of dye in leaves below the dye site. This, combined typical upwards dye travel in the stem, suggests that there is not a very strong vascular effect of damage on leaves located below a site of interest, while leaves above a site of interest should be more strongly influenced by vascular connections.
Figure S1. View from above of plant, with location of dye addition designated 0°. Other leaves were assigned angles based on distance around the stem from the site of dye addition. Dye was generally seen in leaves within 50° of dye addition site, especially at the same node.
Figure S2. Diagram of dye introduction setup and results of vascular architecture mapping. Leaves, parts of leaves, or stems with red color represent areas where Rhodamine-B dye was seen in the vascular tissue after 24 hours.
REFERENCES
Orians CM, Pomerleau J, Ricco R (2000) Vascular architecture generates fine scale variation in systemic induction of proteinase inhibitors in tomato. Journal of Chemical Ecology 26:471-485.
Viswanathan DV, Thaler JS (2004) Plant vascular architecture and within-plant spatial patterns in resource quality following herbivory. Journal of Chemical Ecology 30:531-543.