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Question 1

one whose absence prevents a plant from completing its life cycle or one that has a clear physiological role.

Answer 1

essential element

Question 2

How many elements are essential for the growth of all higher plants?

Answer 2

only 17 elements

Question 3

Importance of first group of essential elements

Answer 3

• forms the organic (carbon) compounds of the plant.
• Plants assimilate these nutrients via biochemical reactions involving oxidation and reduction

Question 4

Importance of second group of essential elements?

Answer 4

• important in energy storage reactions or in maintaining structural integrity.
• present in plant tissues as phosphate, borate, and silicate esters

Question 5

Importance of third group of essential elements?

Answer 5

• roles as enzyme cofactors
• in the regulation of osmotic potentials

Question 6

Role of fourth group of essential elements?

Answer 6

roles in reactions involving electron transfer

Question 7

Is present in plant tissue as either free ions or ions bound to substances such as the pectic acids present in the plant cell wall.

Answer 7

Third group of essential elements

Question 8

Essential mineral elements are usually classified as macronutrients or micronutrients according to what?

Answer 8

to their relative concentration in plant tissue.

Question 9

they are required in large amounts (in excess of 10 mmole kg−1 of dry weight).

Answer 9

Macronutrients

Question 10

are required in relatively small quantities (less than 10 mmole kg−1 of dry weight) and*serve catalytic and regulatory roles such as enzyme activators.

Answer 10

Micronutrients

Question 11

serve as regulators in addition to their structural role.
Which essential elements?

Answer 11

calcium and magnesium (macronutrients)

Question 12

technique of growing plants with their roots immersed in nutrient solution without soil

Answer 12

solution culture or hydroponics

Question 13

when the nutrient concentration in a tissue sample is low, growth is reduced.

Answer 13

deficiency zone

Question 14

the nutrient availability continues to increase, a point is reached at which further addition of nutrients is no longer related to increases in growth or yield but is reflected in increased tissue concentrations.

Answer 14

Adequate zone

Question 15

the minimum tissue content of the nutrient that is correlated with maximal growth or yield

Answer 15

critical concentration of the nutrient

Question 16

the nutrient concentration of the tissue increases beyond the adequate zone, growth or yield declines because of toxicity.

Answer 16

toxic zone

Question 17

essential element is mobile, deficiency symptoms tend to appear first in ……….?

Answer 17

older leaves.

Question 18

Deficiency of an immobile essential element will become evident first in ………………?

Answer 18

younger leaves

Question 19

Deficiency of an immobile essential element will become evident first in older leaves.
T/F?

Answer 19

F, younger leaves.

Question 20

Excess of phosphorous stimulates growth of roots less than shoots, thus reducing the shoot/root ratio
T/F?

Answer 20

F, roots more than shoots