biology-today_2015-03

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Subscribe online at http://www.mtg.in 90 50 8 85 43 65 76 31 26 CONTENTS Vol. XVII No. 3 March 2015 Corporate Office: Plot 99, S ...

TRANSLOCATION OF WATER ANd mINERALS (ASCENT OF SAp) The upward movement of sap (water with dissolved ingredients) from the root ...

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Relay pump theory Relay pump theory was put forward by Godlewski (1884). According to this, upward conduction of water is due to ...

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With the increase of diffusion pressure deficit, these cells absorb water from adjoining cells, ultimately the water is absorbed ...

Stomatal apparatus The stomata are tiny pores present in the epidermal surface of leaves, young stems and in certain fruits (e.g ...

mechanism of stomatal movement Stomata function as turgor operated valves because opening and closing of stomata is governed by ...

malate or K+ ion pump hypothesis This is the most accepted modern theory. It is also known as hormonal regulation theory (due to ...

malic acid. Excess of malic acid inhibits its own synthesis by decreasing the activity of PEP carboxylase. These changes cause r ...

Leaf modifications such as formation of prickles, leaf spines, phyllodes etc., help in reducing the rate of transpiration. Comp ...

the stomatal opening for a period of two or more weeks without influencing other metabolic processes. The most promising of thes ...

BLEEdING It is the exudation of sap or watery solution from the cut or injured parts of the plant, e.g., Agave, Acer, Vitis, etc ...

Since the source-sink relationship is variable, the direction of movement in the phloem can be upwards or downwards, i.e., bi-di ...

The organic substances present in mesophyll cells are passed into the sieve tubes through their companion cells by an active pro ...

New MCQs Ringing/girdling experiments demonstrate (a) phloem is responsible for translocation of food (b) xylem is responsible ...

The process of guttation takes place when (a) the root pressure is high and the rate of transpiration is low (b) the root press ...

The following figure shows the stomatal apparatus. Identify the parts labelled as A, B, C and D and choose the correct answer f ...

Which of the following statements is not true for stomatal apparatus? (a) Guard cells invariably possess chloroplasts and mitoc ...