[HDquiz quiz = “1965”]
[HDquiz quiz = “1962”]
Azolla is a genus of aquatic fern. Azolla is also known as water fern, duckweed fern, or mosquito fern. Azolla belongs to the Salviniaceae family. Azolla is a weed and they grow very fast in a favorable environment. In rice fields, Azolla sps. are used as green manure. Azolla species contain the blue-green algae Anabaena. Anabaena is able to fix atmospheric nitrogen and provide it to the host Azolla. Upon decomposition, Azolla provides nitrogenous manure to the rice plant.
[HDquiz quiz = “1958”]
Golden Rice (Oryza sativa) is a rice variety produced by genetic engineering in which beta-carotene, the precursor molecule of vitamin A is synthesized. The genes incorporated for the production of beta-carotene are phytoene synthase (Psy) isolated from daffodil and phytoene desaturase (Crt1) isolated from the bacterium Erwiniauredovora. The third gene incorporated is lycopene beta-cyclase (Lcy) from daffodil.
The growth of pollen tubes in the embryo sac of plants is due to chemical signals. Chemotropism is the growth of structure in a living organism is due to the stimulation of some chemicals from the outside of the organism. The process is also known as chemotaxis.
Several molecules are secreted by the stigma or part of the female embryo sac to attract pollen tubes are Chemocyanin (Plantacyanins) in lily, Glycosylated tobacco transmitting tissue-specific proteins in tobacco, and cysteine-rich polypeptides LUREs (LURE1 and LURE2).
The insectivorous plants are Nepenthes and bladderwort.
Nepenthes (Nepenthes mirabilis) also known as tropical pitcher plants is a carnivorous plant belonging to the family Nepenthaceae and order Caryophyllales.
The genus Utricularia or Bladderworts are carnivorous plants belonging to the family Lentibulariaceae and order Lamiales. They are mostly found in aquatic habitats. Example: Utricularia amethystina
In flowering plants, the endosperm is the tissue that produces as a result of double fertilization. The endosperm is formed when one of the sperm fertilizes with the diploid secondary nucleus of the central cell. The process is also known as triple fusion. The endosperm provides nourishment to the growing embryo.
The family with the correctly matched plant is “Malvaceae – Cotton”. The cotton (Gossypium herbaceum) is a herbecious, perrinial flowering plant belonging to the family malvaceae.
Mango (Mangifera indica) is a flowering plant belonging to the family Anacardiaceae and not Leguminosae. Orange (Citrus aurantium) is a flowering plant belonging to the family Rutaceae and not Cucurbitaceae. Wheat (Triticum aestivum) is a flowering plant belonging to the family Poaceae and not Brassicaceae.
Diatoms are microscopic photosynthetic algae having a cell size range from 2 to 200 micrometers. One of the important characteristic features of diatoms is the presence of a siliceous skeleton or the frustule. Diatoms are found in every aquatic environment such as freshwater as well as marine waters.
The cell walls of diatoms are made of silica. The silica is mainly composed of hydrated silicon dioxide. When diatoms die, the organic material or the living part decomposes, and the siliceous skeleton (diatomite or diatomaceous earth) settles to the bottom of that aquatic environment.
The undifferentiated cells in plants are meristematic cells. Meristematic cells are chief totipotent cells present in plants that are capable of active cell division to form differentiated tissues and organs in plants. These cells continuously differentiated till they lose the ability to divide.
Meristems are found in gymnosperm, angiosperm (monocot and dicots). Meristematic tissues are present in three different parts of the plants. Apical meristems present at the tips, intercalary meristems present at the middle at nodes/internodes and lateral meristems present at the sides of the plants.