Question

a. Along the Oregon coast you can find a carnivorous “pitcher plant” named Darlingtonia californica, growing in boggy soil. This plant produces two types of leaves, one type is a standard flat leaf used for photosynthesis and the other type where the leaf curls into a pitcher that then fills with water (the “pitchers”) that trap insects that the plant then digests. Why does it need both leaf types if it eats animals?

b. The proportion of each type is dependent on the nitrogen content of the soil – as the nitrogen content increases the ratio of photosynthetic leaves to pitcher leaves changes. Which type of leaf do you think would be more common in very nitrogen poor soil? Why?

Answer 1

a. The pitcher-shaped traps in pitcher plants trap prey in a rolled leaf containing a pool of digestive enzymes and bacteria to digest organisms. It also contain flat leaves because, cobra lilies (Darlingtonia californica) need as much energy from photosynthesis as possible to compensate for poor soil conditions.

The bulk of its nutrition in pitcher plants are comes from insects and the remainder from photosynthesis, which can only meet energy needs of plant. So, both types of leaves: curly leaves and flat leaves are essential for the survival of pitcher plants.

b. The curly leaves are often more common in very nitrogen poor soil.

Plants need nitrogen for making amino acids, nucleic acids, etc. Pitcher plants grown in poor nitrogen containing soil needs deficient in nitrogen. Therefore, pitcher plants need another mechanism to meet their need. Insects contain proteins. Pitcher plants absorb, breaks these protein and thereby synthesise proteins for their own growth. The curly leafs are adapted to carnivorous lifestyle. Pitcher plants are adapted to grow in poor nutrient containing soils, especially low nitrogen content. In order to survive in this soil, carnivorous lifestyle is necessary for the plant instead of having photosynthesis only.