Intercellular Co 2 Concentration - PP Systems CIRAS-3 Operating Manual

(5.1) IRGA CO readings are corrected for water vapor, temperature, and atmospheric pressure. The
2
addition of transpirational water vapor dilutes the air leaving the cuvette (C
for in the calculation:
(5.2) To calculate net CO2 assimilation we rearrange equation (5.1) to:
CIRAS-3 calculates and displays the CO
CIRAS-3 display:
Intercellular CO
2
Calculate CO concentration in the sub-stomatal cavity (C
2
& Farquhar, 1981
(6.1) The sub-stomatal CO2 concentration, C
(6.2) Where g is the total conductance to CO
c
��
(1.585 is the diffusion ratio of CO
boundary layer).
Note: These calculations are based on the following assumptions:
·
the leaf is exposed on both upper and lower leaf surfaces
·
the upper and lower boundary layer resistances are similar
·
stomata are evenly distributed on both upper and lower leaf surfaces.
CIRAS-3 Operation Manual V. 1.09
�� = ( ��
����
�� = −�� ( ��
������
difference (C
2
= ( ������
��
������
Concentration
�� ��������� ������
��
��������� �� �� � = �
−�� −��
��
and water in air, and 1.37 is the diffusion ratio of CO
2
× �� ) − [ �� × ( �� + �� )]
������
− �� ) × ��� + ( ��
���� ������
- C ). As relates to the calculated values in the
out in
) = ������
+ ������
�� ��
) using the equation derived by von Caemmerer
i
, is given by:
i − � × ��
����
��
� =
��
��
−��
��� +
��
��
��
��
transfer:
2
( ��. ������ × �� ) + ( ��. ���� × ��
��
162
), and this is compensated
out
× �� ) �
��
� − ��
������
�
� × ����
��
)
��
and water in the
2
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