LUCIANO, CARL L., SANDRA J. NEWELL*, ANTHONY J. NASTASE, ANNA M. HARDING, AND R. LISA ROUNTREE. Department of Biology, Indiana University of Pennsylvania, Indiana, PA 15705. - Pitcher ontogeny and production of digestive enzymes in the carnivorous pitcher plant, Sarracenia purpurea.
We described pitcher ontogeny for Sarracenia purpurea grown
under controlled conditions. Fifteen pitchers were observed in a
chamber with 14h:10h photoperiod, 23C:15C temperature regime, and >60%
relative humidity. Measurements of pitcher length began when pitchers
reached 1cm (Day 0) and continued daily for 45 days. Pitchers
exhibited sigmoid growth, reaching maximum size (mean = 8.3cm, std.
error = 0.39) after 26 days. On average, pitchers opened on Day 23,
formed the nectar roll by Day 27, and visibly produced nectar by Day
34. Nectar accumulated in viscous, sweet globules on the pitcher. A
second goal was to measure activity of digestive enzymes in newly
opened pitchers. Prior to opening, individual pitchers were covered
with sterile plastic bags. After opening, several pitchers received
small quantities of "ant soup", i.e., ants placed in
distilled water and autoclaved to sterilize the soup and denature any
enzymes present in the ant. After 1-3 days pitcher fluid was analyzed
for activity of proteases and acid phosphatase and was plated onto
several kinds and pHs of agar to check for presence of bacteria. Acid
phosphatase was present in pitcher fluid even when agar plates showed
no bacterial growth. As yet, we have been unable to find protease
activity in the absence of bacteria. We concluded that pitchers of
Sarracenia purpurea are capable of producing acid phosphatase
and potentially other enzymes. Digestion in these pitchers is not
entirely dependent on the inhabitants of the aquatic ecosystem in the
pitcher.
Key words: acid phosphatase, carnivorous plant, digestive enzyme, ontogeny, pitcher plant, Sarracenia purpurea