Pinguicula, commonly known as the butterworts, is a genus of carnivorous plants that use sticky, glandular leaves to lure, trap, and digest insects in order to supplement the poor mineral nutrition they obtain from the environment. Of the roughly 80 currently known species, 12 are native to Europe, 9 to North America, and some in northern Asia. The largest number of species is in South and Central America.
The leaf blade of a butterwort is smooth, rigid, and succulent, usually bright green or pinkish in colour. Depending on species, the leaves are between 2 and 30 cm.(1-12") long. The leaf shape depends on the species, but is usually roughly obovate, spatulate, or linear.
Vector graphic of the trapping and digestive features of a Pinguicula leaf
Like all members of the family Lentibulariaceae, butterworts are carnivorous. In order to catch and digest insects, the leaf of a butterwort uses two specialized glands which are scattered across the leaf surface (usually only on the upper surface, with the exception of P. gigantea and P. longifolia ssp. longifolia). One is termed a peduncular gland, and consists of a few secretory cells on top of a single stalk cell. These cells produce a mucilagenous secretion which forms visible droplets across the leaf surface. This wet appearance probably helps lure prey in search of water (a similar phenomenon is observed in the sundews). The droplets secrete limited amounts of digestive enzymes, and serve mainly to entrap insects. On contact with an insect, the peduncular glands release additional mucilage from special reservoir cells located at the base of their stalks. The insect will begin to struggle, triggering more glands and encasing itself in mucilage. Some species can bend their leaf edges slightly by thigmotropism, bringing additional glands into contact with the trapped insect. The second type of gland found on butterwort leaves are sessile glands which lie flat on the leaf surface. Once the prey is entrapped by the peduncular glands and digestion begins, the initial flow of nitrogen triggers enzyme release by the sessile glands.These enzymes, which include amylase, esterase, phosphatase, protease, and ribonuclease break down the digestible components of the insect body. These fluids are then absorbed back into the leaf surface through cuticular holes, leaving only the chitin exoskeleton of the larger insects on the leaf surface.
The holes in the cuticle which allow for this digestive mechanism also pose a challenge for the plant, since they serve as breaks in the cuticle (waxy layer) that protects the plant from desiccation. As a result, most butterworts live in humid environments.
Flower of P. vulgaris
Butterworts are usually only able to trap small insects and those with large wing surfaces. They can also digest pollen which lands on their leaf surface. The secretory system can only function a single time, so that a particular area of the leaf surface can only be used to digest insects once.
Whitout photomaker program.
Natural, no effect, no filter. Natural photo.
Uploaded: Jun 28, 2016