In biological nitrogen fixation, the atmospheric $\mathrm{N}_2$ gets reduced to $\mathrm{NH}_3$ by nitrogenase reductase present in some prokaryotes. $\mathrm{NH}_3$ is then oxidises to $\mathrm{NO}_2$ and $\mathrm{NO}_3$ by some other bacteria (Nitrosomonas and Nitrobacter). Various steps involved in nitrogenfixation are as follows
Pseudomonas and Thiobacillus are involved in the process of denitrification. They convert nitrate $\left(\mathrm{NO}_3^{-}\right)$and nitrite $\left(\mathrm{NO}_2^{-}\right)$into free nitrogen $\left(\mathrm{N}_2\right)$, which is released into the atmosphere.
Carefully observed the following figure
(a) Name the technique shown in the figure and the scientist who demonstrated this technique for the first time.
(b) Name atleast three plants for which this technique can be employed for their commercial production.
(c) What is the significance of aerating tube and feeding funnel in this setup?
(a) Hydroponics, Julius Von Sachs (1860)
(b) (i) Solanum lycopersicum (tomato)
(ii) Hibiscus asculentus (ladiesfinger)
(iii) Solanum melongena (brinjal)
(c) Aerating tube Provides oxygen for the normal growth and development of the roots growing in the liquid solution. Feeding funnel is used to add water and nutrients in the hydroponic system when required.
| Critical Concentration | Deficient |
|---|---|
| A concentration of a nutrient measured in tissue, just below the level that gives maximum growth is defined as critical concentration. e.g., N, P and K are known as critical elements. |
The concentration that is below the critical concentration and the deficiency of nutrient element can lead to a gradual fall in the plant growth is called deficient. |
| Critical concentration | Deficient | |
|---|---|---|
| Zn | 0.5-1% | less than 0.5% |
| Fe | 3.5-5% | less than 3.5% |
Carnivorous plants exhibit nutritional adaptation. Citing an example explain this fact.
