Nutrition In Plants – Mineral Nutrition — Practice Quiz

As nitrate ion (NO₃⁻) or ammonium ion (NH₄⁺)

Step 1: Plants absorb most mineral elements in ionic (charged) forms dissolved in water. Step 2: Nitrogen, despite being abundant as N₂ gas in the atmosphere (78%), cannot be directly absorbed by most plants from air. Step 3: Most plants absorb nitrogen from the soil in the form of nitrate ions (NO₃⁻) or ammonium ions (NH₄⁺). Step 4: Only certain bacteria and cyanobacteria (blue-green algae) can fix atmospheric N₂ directly – this is called nitrogen fixation. Step 5: Urea is a fertilizer that first gets converted to ammonium in soil before plants absorb it. So the direct answer is NO₃⁻ or NH₄⁺

Molybdenum (Mo)

Step 1: This question asks about a specific micronutrient with two key roles. Step 2: Molybdenum (Mo) is absorbed as MoO₂²⁺ ions and is required by all plant tissues, particularly in roots. Step 3: Its two most important functions are: (a) Required for nitrogen fixation, and (b) Activates the enzyme nitrate reductase (which converts nitrate to usable forms). Step 4: Manganese activates enzymes of photosynthesis and respiration. Zinc activates dehydrogenases and is a component of auxin (IAA). Copper is a component of oxidase enzymes and plastocyanin. Step 5: Only Molybdenum is specifically link

Parasitic nutrition

Step 1: Let's recall what Cuscuta (Amarbel/Akashbel/Dodder) is and how it gets nutrition. Step 2: Cuscuta lacks chlorophyll and leaves, so it CANNOT perform photosynthesis – ruling out autotrophic nutrition. Step 3: It is a yellow climber that attaches itself to a living host plant and produces haustoria (suckers) that penetrate the host's phloem to absorb nutrition. Step 4: Since it draws nutrition from a LIVING host (not dead matter), it is a PARASITE, not a saprophyte. Saprophytes like Monotropa feed on DEAD organic matter. Step 5: Insectivorous plants (like Nepenthes) trap insects, which i

In Aeroponics, roots are suspended in a humid air environment and misted with nutrients, while in Hydroponics, roots are submerged in nutrient solution

Step 1: Both Hydroponics and Aeroponics are soil-free methods of growing plants, but they differ in how roots receive nutrients. Step 2: In Hydroponics: roots are submerged or immersed in a nutrient solution (water-based). Vigorous aeration is needed to supply oxygen to roots. Step 3: In Aeroponics: roots are placed inside a special box with computer-controlled humid atmosphere. The roots are misted/sprayed with nutrient solution for short durations – roots grow in AIR, not water. Step 4: Hydroponics is used commercially (cucumber, tomato, lettuce). Aeroponics is relatively newer and is partic