Description Sarracenia

1 description

1.1 carnivorous mechanism
1.2 flowers , seeds
1.3 growth cycle
1.4 genetics

description

sarracenia herbaceous perennial plants grow subterranean rhizome, many tubular pitcher-shaped leaves radiating out growing point, , turning upwards trap openings facing center of crown. trap vertical tube hood (the operculum) extending on entrance; , below top of tube has rolled lip (the peristome) secretes nectar , scents. hood produces nectar too, in lesser quantities.

the inside of pitcher tube, depending on species, can divided 3 5 distinguishable zones: zone 1 operculum (or hood), zone 2 peristome , rest of trap entrance, while zones 3 , 4 (which in species combined) , 5 (only present in s. purpurea) further divisions of actual tube. each of these zones has specific function, corresponding morphophysiological characteristics.

zone 1: operculum. in species operculum covers @ least part of pitcher opening, preventing rain excessively filling pitcher, result in loss of prey , dilute digestive fluid. operculum serves guide prey pitcher opening, using combination of color, scent, , downward-pointing hairs lead insects toward trap entrance. species, s. minor , s. psittacina, have opercula hang low on pitcher entrance. these studded chlorophyll-free patches, translucent windows confuse prey attempting fly through operculum, thereby causing them cascade down pitcher tube. (a similar, better-developed mechanism found in closely related darlingtonia californica).
zone 2: peristome , trap entrance. zone composed of peristome, produces copious amounts of nectar, luring insect prey land or crawl onto perilous footing surrounding pitcher trap. zone includes waxy upper portion of pitcher tube. footing on zone treacherous, waxy deposits on surface of zone cause unwary insects lose footing , tumble pitcher depths.
zone 3: located below zone 2, zone features leaf surface non-existent footing, coating of ultra-fine, downward pointing hairs. insects have made far lose chance of escape. studded digestive glands, secrete digestive enzymes digestive fluid.
zone 4: final zone in species. filled digestive fluids, , readily absorbs nutrients released insects work of digestive enzymes , bacteria in pitcher fluid. along more digestive glands, zone features thick coating of coarse downward pointing hairs, makes escape digestive fluids impossible.
zone 5: zone, located below zone 4 , found in s. purpurea, smooth, glabrous, lacks glands, , not serve absorptive zone. function unknown.

carnivorous mechanism

all sarracenia trap insects , other prey without use of moving parts. traps static , based on combination of lures (including color, scent, , nectar) , inescapability – typically entrances traps one-way virtue of highly adapted features listed above.

most species use combination of scent, drugged nectar, waxy deposits (to clog insect feet) , gravity topple insect prey pitcher. coniine, alkaloid drug narcotic insects, has been discovered in nectar-like secretions of @ least s. flava. once inside, insect finds footing slippery waxy surface covering walls of pitcher. further down tube, downward-pointing hairs make retreat impossible, , in lowest region of tube, pool of liquid containing digestive enzymes , wetting agents drowns prey , begins digestion. exoskeletons not digested, , on course of summer fill pitcher tube.

only s. purpurea contains significant amounts of rainwater in tubular pitchers. myth species contain water. in fact, hoods of other species keep out rain water in addition keeping flying prey escaping.

s. psittacina, parrot pitcher, uses lobster-pot style trap admit prey (including tadpoles , small fish during floods) not allow find way out; , sharp inward-pointing hairs force victim gradually down base of pitcher digested.

flowers , seeds

cutaway view of sarracenia flower

flowers produced in spring, or ahead of first pitchers. held singly on long stems, above pitcher traps avoid trapping of potential pollinators. flowers, depending on species 3–10 centimeters in diameter, dramatic , have elaborate design prevents self-pollination. consists of 5 sepals superintended 3 bracts, numerous anthers, , umbrella-like five-pointed style, on 5 long yellow or red petals dangle. whole flower held upside-down, umbrella-like style catches pollen dropped anthers. stigmas located @ tips of umbrella-like style. primary pollinators bees. bees searching nectar must force way past 1 of stigmas enter chamber formed style. inside, inevitably come in contact lot of pollen, both hanging anthers , pollen collected style. upon exiting, bees must force way under 1 of flap-like petals. keeps them away stigma, avoiding self-pollination. next flower visited receives on stigmata of first flower s pollen, , cycle continues.

sarracenia alata flowers

floral formula: ca co g

the flowers of species scented. scent varies, strong , unpleasant. s. flava has strong odor resembling cat urine.

flowers last 2 weeks. @ end of flowering period, petals drop , ovary, if pollinated, begins swell. seed forms in 5 lobes, 1 lobe producing smaller numbers of seeds other lobes. on average, 300–600 seed produced, depending on species , pollination success. seed takes 5 months mature, @ point seed pod turns brown , splits open, scattering seed. seeds 1.5–2 mm in length , have rough, waxy coat makes hydrophobic, possibly seed dispersal flowing water. sarracenia seed requires stratification period germinate in large numbers. plants grown seed start producing functioning traps immediately, although differ in morphology adult traps first year or so, being simpler in structure. plants require 3–5 years reach maturity seed.

growth cycle

pitcher production begins @ end of flowering period in spring, , lasts until late autumn. @ end of autumn, pitchers begin wither , plants produce non-carnivorous leaves called phyllodia, play role in economics of carnivory in these species. since supply of insects during winter decreased, , onset of cold weather slows plant metabolism , other processes, putting energy producing carnivorous leaves uneconomical plant.

genetics

the genus has been found have chromosome number of 2n=26, though earlier studies had found number 2n=24.