Mineral nutrition practice · Easy

Option D (I and IV) is correct because nitrogen is primarily required by meristematic tissues for cell division and metabolically active cells for protein and nucleic acid synthesis.

Option A (Chelate metals) is correct because chelating agents are used in hydroponics to bind to metal ions, preventing them from precipitating and making them more available to plants.

Option B (Denitrification) is correct because denitrification is the process where nitrates are converted back into atmospheric nitrogen.

Option B (Passive uptake) is correct because the first phase of mineral absorption is rapid and does not require energy, indicating passive transport.

Option D (All of these) is correct because nitrification involves the conversion of ammonia to nitrite and then nitrite to nitrate.

Option B (Upon successful infection of the root hair) is correct because curling of root hair occurs after Rhizobium successfully infects the root hair, initiating nodule formation.

Option C (Botanist) is correct because Julius Von Sachs was a German botanist who significantly contributed to plant physiology, including demonstrating hydroponics.

Option A (Bacillus polymixa) is correct because Bacillus polymixa is a free-living nitrogen-fixing bacteria.

Option A (Only IV) is incorrect and Option C (IV and II) is also incorrect. The correct answer is weathering of rocks. Soil maintains a regular supply of minerals primarily through the weathering of rocks, which releases minerals into the soil. While activity of decomposers is important for nutrient cycling, it doesn't maintain a *regular* supply of minerals in the same way that weathering does. Slow vegetation is not a factor in maintaining mineral supply. Therefore, none of the provided options are fully correct, but weathering of rocks is the closest single correct answer. Since the question forces a choice, we must select the best available option, which is A (Only IV).

Option D (B) is correct because boron (B) is a micronutrient, while magnesium (Mg), sulphur (S), and calcium (Ca) are macronutrients.

Option B (Nutrient solution) is correct because hydroponics involves growing plants without soil, using a nutrient-rich water solution.

Option A (17) is correct because there are 17 essential mineral elements required for plant growth.

Option B (Fe, Cu) is correct because iron (Fe) and copper (Cu) are essential components of enzymes involved in redox reactions in plant cells.

Option A (Rhizobium) is correct because Rhizobium is a nitrogen-fixing bacteria that is symbiotic and not photoautotrophic. Chlorobium, Nostoc, and Anabaena are photoautotrophs.

Option D (Ca, Mg, Cu and K) is correct because deficiency of Calcium (Ca), Magnesium (Mg), Copper (Cu), and Potassium (K) can lead to necrosis, which is the death of plant tissues, particularly leaf tissue.

Option A (Delaying of flowering) is correct because nitrogen deficiency often leads to delayed flowering due to its role in overall plant growth and development.

Option B (Adequately aerated) is correct because hydroponic systems require adequate aeration to ensure the roots receive sufficient oxygen for respiration and nutrient uptake.

Option D (both A and B) is correct because low concentrations of Nitrogen, Sulfur, and Molybdenum can inhibit cell division and delay flowering in plants.

Option C (Acidic) is correct because most vegetables prefer a slightly acidic pH range for optimal nutrient uptake in hydroponic systems.

Option A (${N_2} \to N{H_3}$) is correct because biological nitrogen fixation is specifically the conversion of atmospheric nitrogen gas ($N_2$) into ammonia ($NH_3$).

Option A (Parts per million) is correct because parts per million (ppm) is the standard unit for measuring the concentration of nutrients in hydroponic solutions.

Option B (Nitrogenase) is correct because nitrogenase is the enzyme complex responsible for reducing atmospheric nitrogen to ammonia in leguminous root nodules.

Option A (Passive diffusion) is correct because ${H_2}O$, ${O_2}$, $C{O_2}$ and Na follow their concentration gradient across the membrane without requiring energy or a carrier protein in Nitella.

Option B (Mineral salts absorbed by plants) is correct because plant ash is the residue left after burning a plant, consisting primarily of mineral salts that the plant absorbed from the soil.

Option B (Essential element below which plant growth is retarted) is correct because critical concentration is defined as the concentration of an essential element below which plant growth is retarded.

Option C (Soilless cultivation of plants) is correct because aeroponics specifically refers to growing plants without soil, using air and nutrient solutions.

Option B (Nitrogen fixation) is correct because the enzyme nitrogenase is specifically responsible for converting atmospheric nitrogen into ammonia.

Option D (All of the above) is correct because all the statements regarding amides, legumes, and leghaemoglobin are accurate.

Option A (As important as macronutrients but are required in small amount) is correct because micronutrients are essential for plant growth but needed in smaller quantities compared to macronutrients.

Option C (17) is correct because there are 17 essential elements required for plant growth and reproduction.