Page 1 - 4.Lesson notes-Heterotrophic nutrition (I)- Parasitic and insectivorous plants.
P. 1

SAI International School

                                               Subject- Biology, Class-VII
                                                Topic-Nutrition in plants
                                         Subtopic- Heterotrophic nutrition (I)
                                                       Lesson notes
               HETEROTROPHIC NUTRITION


                   •  The mode of nutrition in which organisms depend upon other organisms for food.

                   •  Heterotrophs- Organisms that cannot make their own food and depend upon others for

                       the food. Ex- All animals, Monotropa and non-green plants like Cuscuta


               1.  PARASITIC PLANTS -

                   •  Heterotrophic plant that lives on another living plant and derives some or all of its

                       nutritional requirements from the host plant.

                   •  The plant from which the parasite derives its nutrients is called a host.
                   •  All parasitic plants have modified roots, named haustoria, which penetrate the host

                       plants, connecting them to the conductive system – either the xylem, the phloem, or

                       both. Ex- Cuscuta, Rafflesia

                   •  Certain plants are partial parasites as they can prepare their own food but depend on

                       other plants for the need of water and minerals. Ex- Mistletoe

                   FACTS – Mistletoe – pretty but sneaky!
                   Mist  letoe, often seen during Christmas, is a partial parasite—it makes some of its
                   own food but still depends on other plants for water and minerals.



               2.  INSECTIVOROUS PLANTS-

                   •  The plants that feed on insects by trapping and digesting them are called insectivorous
                       plants. Ex- Pitcher plant, Venus fly trap, Sundew, Bladderworts etc.

                   •  This is a kind of holozoic nutrition.

               Insectivorous plants can photosynthesise. But they grow on soil which is deficient in nitrogen.
               So, they feed on insects to fulfil their requirement of nitrogen.
   1