Breath. Respirometr Varburga

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Respirometr Varburga intended for measurements of gas exchange at constant volume (fig. 5.12), has been designed by German biologist Otto Varburgom more 50 years ago. Oi allows to measure speed of absorption О2 and allocation СО2 by vegetative fabrics. The device consists of a great number sosudikov, the manometre is attached to each of which, giving the chance to watch how varies in given sosudike pressure of gas. In sosudiki place small sprouts, seeds, parts of a plant or culture of cages. Temperature and volume sosudikov to which manometres,

Support constants, and, hence, changes in pressure of gases inside sosudikov are caused only by absorption of gas by a vegetative fabric or liberation of gas from it. Are absorbed by a fabric and two gases - oxygen and carbon dioxide are allocated from it mainly; pressure change also depends on their absorption or allocation in sosudikah.

A temperature and volume Constancy sosudikov - the important condition because both these sizes influence pressure which is connected with them the following dependence:

Where R - pressure, V - volume and T - temperature. For maintenance of constant temperature sosudiki immerse in termostatirovannuju a bath, and a constancy of volume of everyone sosudika provide, establishing by means of the press crane a liquid in a manometre before the experience beginning at zero level. Changes in the pressure, the temperatures of a water bath connected with small fluctuations, register in control sosudike, not containing the investigated sample. The same control allows to consider and changes in atmospheric pressure.

Respirometr Varburga gives the chance to measure absorption of oxygen irrespective of allocation СО2. For this purpose central tsilindrik, being inside sosudika with the sample of a vegetative fabric, fill with any strong alkali, for example caustic kali (GAME). СО2 it is good rastvorima at high values RN and it is continuously absorbed by the alkali, therefore all changes in pressure in these conditions depend only on oxygen. it is more difficult to spend the measurements concerning СО2. The Most direct method consists that measurements spend simultaneously with two identical samples to two sosudikah from which only one contains the GAME. In sosudike about the GAME of change of pressure will be caused only by absorption О2, and in sosudike without the GAME they will depend both on absorption О2, and from allocation СО2. It allows on a difference between speeds of gas exchange in two such sosudikah to define speed of allocation СО2.