Ch 12Mineral Nutrition — Class 11 Botany, concept-first.

As a traveller moving through different landscapes, you may have noticed that plants are never entirely alike - some grow lush with vivid leaves, flowers and fruit, while others nearby look stunted, d…

Based on how much of each element a plant tissue actually needs, essential minerals fall into three groups (Table 12.1).

Whether a deficiency symptom shows up first on a plant's oldest leaves or its youngest leaves depends entirely on how mobile that particular mineral is inside the plant (Figure 12.1).

Minerals can equally be classified by the specific biochemical function each one performs. Structural component minerals - carbon, hydrogen, oxygen and nitrogen - are built directly into the organic m…

Macronutrients are required in the largest quantities and each has a well-defined role, absorbed form, and deficiency picture.

Micronutrients are needed only in trace amounts but are just as essential to metabolism as macronutrients, and several also play specific roles in individual crops.

Table 12.2 groups mineral deficiency symptoms by the name of the disease or symptom they produce and lists which minerals are responsible for each.

Knowing a mineral's critical concentration matters for two practical reasons: it tells a grower the minimum tissue level needed to avoid deficiency symptoms, and it warns against oversupplying a miner…

Figure 12.2 plots growth rate (as a percentage of the maximum) against the concentration of a mineral nutrient in plant tissue, and the resulting curve has four zones.

Several minerals cause specific problems once their concentration exceeds the adequate range. Manganese toxicity blocks the uptake of iron and magnesium and prevents calcium from being translocated to…

Von Sachs first demonstrated in 1860 that a plant could be grown to full health in a defined nutrient solution with no soil at all, and later researchers formulated standard recipes for this purpose,…

Nitrogen makes up about 78% of the atmosphere in its molecular form, N2, but the two nitrogen atoms in this molecule are held together by an unusually strong triple covalent bond, which makes N2 chemi…

Nitrogen can be fixed by purely physical or industrial means, without any organism's involvement. In industry, atmospheric nitrogen is fixed by chemical processes under controlled conditions to manufa…

Most of Earth's fixed nitrogen comes from living organisms rather than from lightning or industry. Symbiotic nitrogen fixation happens through a close physical partnership between a nitrogen-fixing or…

Fixed nitrogen does not stay put once it enters the soil - it is continuously converted between chemical forms and cycled between the atmosphere, the soil and living organisms by a sequence of largely…

The nitrogen cycle proceeds through five linked stages. In fixation, the nitrogenase enzyme complex progressively reduces atmospheric di-nitrogen (N-N, triple bonded) by adding pairs of hydrogen atoms…

Ammonia produced by nitrogen fixation or nitrate assimilation cannot be allowed to accumulate freely, since it is toxic to cells, so plants convert it into amino acids through two routes, together cal…

Nutrition, broadly, is the uptake and use of nutrients by any living organism, and it falls into two main types.

Saprophytes obtain their nutrients from dead and decaying organic matter, a mode of nutrition typical of bacteria and fungi but adopted by a small number of angiosperms as well.

Parasitic angiosperms take their nutrients from a living host plant and, in doing so, damage or disease it. They fall into two groups depending on how completely they depend on the host.

Several genuinely mutualistic partnerships bear directly on plant mineral nutrition. Lichens are a close mutual association between an alga and a fungus, in which the alga photosynthesises and supplie…

Insectivorous (carnivorous) plants grow in nitrogen-deficient soils, such as bogs and marshes, and have evolved modified leaves that trap and digest insects to supplement the nitrogen their roots cann…

These questions cover mineral classification and function, deficiency and toxicity symptoms, the mobility of minerals within a plant, nitrogen fixation and the nitrogenase enzyme, and the insectivorou…

Sample papers and previous-year board questions for this subject.