Plant Nutrition and Adaptations - Class XI

Utricularia are carnivorous plants which capture small prey with remarkable suction traps. These are rootless plants formed of very thin, forked leaves. Only the flower remain out of the water while the whole trap is underwater. When an aquatic animal touches its sensitive hairs, the traps suck it in, in just a few seconds, along with water, which is then drained through its walls.

Plants which synthesise their food themselves are called autotrophs. That is, it doesn't depend on other organisms for food, using sunlight and water the plants makes their own food. They are considered as the producers in a food chain. Saprotrophs are the plants which feeds from the dead and decayed organic matters knows as detritius. Major saprotroph group includes fungi, bacteria and water molds.

A bisexual flower (or “perfect”) has both stamens and carpels, and a unisexual flower (or “imperfect”) lacks stamens is called staminate.

(A) Insectivorous plants are the plants that feed on insects.

A facultative saprophyte is an organism that is primarily a parasite but has the ability to survive as a saprophyte (feeding on dead organic matter) under certain conditions.

Balanophora is a well known example of a parasitic plant that attaches to the roots of host plants to obtain nutrients, making it a root parasite.

• An epiphyte is an organism that grows on the surface of a plant and derives its moisture and nutrients from the air, rain, water or from debris accumulating around it.
• Most epiphytic orchids are found growing in tropical areas below the canopy of trees. Epiphytic orchids have adapted to obtain water and nutrients that grow with their roots which are located aerially.
  
• They have thick, spongy roots that absorb and store water and nutrients from the sporadic rainfall to be used over time.
  

• Pitcher plants are several different carnivorous plants which have modified leaves (act as a pitcher) which are known as pitfall traps—a prey-trapping mechanism featuring a deep cavity filled with digestive liquid. 
• These plants trap harmful insects and kill them with the help of digestive fluid.

Symbiosis is any type of close and long-term biological interaction or relationship between two different biological organisms, be it mutualistic or commensalistic. It is usually a form of beneficial relationship in which both organisms are benefited.

• A parasite is an organism that lives on or in a host organism and gets its food or nutrition from its host (plants and animals). There are three main classes of parasites that can cause disease in humans: protozoa, helminths, and ectoparasites.
• Parasites come in many shapes and sizes and include viruses and bacteria, various worms, plants, fungi, insects, and even birds and mammals.
  

• Drosera, commonly known as the sundews, is one of the largest genera of carnivorous plants with at least 194 species.
•  They lure, capture, and digest insects using stalked mucilaginous glands covering their leaf surfaces. 
• Sundews are perennial (or rarely annual) herbaceous plants. Sundews have been shown to be able to achieve a lifespan of 50 years.

• A lichen is a symbiotic association between one or two fungus species and an alga or cyanobacterium (blue-green algae). Lichens were once classified as single organisms, until the advent of microscopy, when the association of fungi with algae or cyanobacteria became evident.
• Lichens may have powdery masses on their surface. These are the tiny bits of the lichen body which will be shed to form new lichens.
  

Algal bloom is a rapid increase or accumulation in the population of algae in an acquatic system. The nutrients like potassium and nitrogen are key nutrients for the growth of algae. The presence of these materials and availability of sunlight are key factors for the growth of algae.

Dodder plant, which belongs to the genus Cuscuta is a yellow, orange, or red (rarely green) parasitic plants. After dodder attaches itself to a plant, it wraps itself around it. If the host contains food beneficial to dodder, the dodder produces haustoria that insert themselves into the vascular system of the host. The original root of the dodder in the soil then dies.

For the canopy to spread over a large area the root system also has to be robust so as to provide enough nutrients and anchorage. Wide spreading and deep roots are tap root systems that are characteristic to dicotyledonous plants.

A parasite depends on its host to stay alive. Killing the host before the reproduction destroys parasite also as it needs host to produce its progeny generation after generation. This makes option D correct. In order to keep the host alive to produce many generations of parasite offspring, it is necessary for a parasite to become less virulent or gentle over many generations. This makes option A incorrect. Fast reproduction produces increase the number of parasite offspring but poses extra burden on host and makes the host survival harder. This makes option B incorrect. Similarly, sticking too long to a host decreases its survival chances and hence, parasite keeps switching the host over time. Option C is incorrect. Thus, the correct answer is option D.

Cuscuta (Dodder) plant is an obligate or total stem parasite. It lacks chlorophyll and has no connection with the soil after the seeding stage. Therefore it is totally dependent on the host for organic food materials and supply of water and minerals salts. The parasitic plant pierces the stem and sucks the nutrients from the host plant.

Rafflesia is a genus of parasitic flowering plants. It contains approximately 28 species, all found in southeastern Asia, in Indonesia, Malaysia, Thailand and the Philippines. It is not a saprophytic angiosperm. Cuscuta, Loranthus and santalum are stem parasites. Nepenthes, Drosera and Dionaea are the insectivorous plants. Mangrove plants are seen in saline marshy lands. 

• Trypsin is working as a digestive enzyme to break down proteins in the small intestine.
• Some plants eat insects. Such plants are called insectivorous plants. They trap and digest insects. The insect is then digested by the enzyme pepsin secreted by the cells of the plants. Example -The protease secreted in the pitcher fluid is pepsin-like.
• Pectinase is the enzyme that breaks down pectin and polysaccharides found in plant cell walls.
• Cellulase is the enzyme that converts cellulose into glucose or a disaccharide.

So option B is correct.

Carnivorous plants are autotrophic but grow in nutrient-poor soil, so they trap small organisms like insects to obtain nitrogen. They do not consume larger animals or humans.

Nepenthes, commonly known as pitcher plants, are often colloquially referred to as man-eater plants in myths, though they only consume small insects.

Aldrovanda is an insectivorous plant as it feeds on insects. Aldrovanda vesiculosa, commonly known as the waterwheel plant, captures small aquatic invertebrates using traps similar to those of the Venus flytrap. The traps are arranged in whorls around a central, free-floating stem.

In flowering plants, the tapetum is the innermost layer of the anther wall that provides nutrients to developing microspores and contributes substances to the pollen wall, including those involved in self-incompatibility.

In Bryales (true mosses), the sporophyte development involves the differentiation of the archesporium from the amphithecium layer of the capsule.

Sporophytic self-incompatibility is typically associated with 2-celled pollen at the time of shedding. 3-celled pollen is characteristic of gametophytic self-incompatibility systems.

The pairing R. Meliloti with Trigonella foenum-graecum is incorrect because R. meliloti typically nodulates Medicago, Melilotus, and Trigonella, but the specific pairing listed here is often cited as a mismatch in specific textbook contexts regarding host specificity.

Matching the plants to their correct botanical names: Cassava is Manihot esculenta (a3), Clusterbean is Cyamopsis tetragonoloba (b2), Radish is Raphanus sativus (c4), and Turnip is Brassica rapa (d1). This matches option B.

Rafflesia is the largest flower that is found on the earth. It is an angiosperm and is an obligate root parasite. An obligate root parasite is the one that cannot complete its life cycle without the presence of a host and derive the nutrition from the host entirely.

Epiphytes are the plants which grow on the other plants for the support as they are weak themselves. They don't harm the plant on which they grow. They obtain their nutrients and moisture from the air. For example : mosses.

Arceuthobium is the genus of parasitic plants. The host of this plants are members of Pinaceae and Cupressaceae. The stem is reduced and the leaves are minute structures. The flowers are sessile. Most of the parasitic plant is covered beneath the bark of the host plant. 

The aerial roots of plants absorb moisture from the air. These roots are seen in epiphytes which grow on the surface of other plants.  Epiphytic plants take nutrition from air, rain and surrounding organic debris, as they are not in contact with soil. Orchids are epiphytes which have aerial roots with a modified spongy layer of the epidermis called velamen which can absorb moisture from humid air. The cells of velamen absorb water during rains and store for future.

Aldrovanda is a free-floating and rootless aquatic plant. It functions as a snap-trap carnivore under water. A common name for it is the waterwheel plant, because a single whorl of leaves, cut from a stem, is wheel-like. Snap traps are only found in one other carnivorous plant genus, Dionaea, which comprises the commonly known Venus flytrap. 

Like all green plants, pitcher plants use their leaves to harness energy from the sun and make their own food; they use carbon dioxide (CO$ _{2}$) to make energy-rich carbohydrates. So, they are producers. 

Saprophytes are the class of organism that have saprophytic mode of nutrition. They feed on dead living organism. They are assumed to have evolved from green plants but have lost their chlorophyll during the course of evolution.

Monotropa (Indian pipe) and Neottia (bird's-nest orchid) are classic examples of myco-heterotrophic plants that function as saprophytes, obtaining nutrients from decaying organic matter via fungal intermediaries.

Stems can be modified to store food and survive unfavorable conditions as perennating organs, common examples being underground stem modifications like tubers (potato) and rhizomes (turmeric). Chrysanthemum and ginger also use underground stems, but potato and turmeric are classic textbook examples of tuber and rhizome modifications respectively.

Weak stemmed plants climb over the support are called twinners. They climb by the stem itself.