A practical approach to estimate diffusional leakages of leaf chamber of open gas exchange systems using intact leaves

Gas exchange (assimilation, transpiration, water use efficiency, and conductance) of `Shawnee' blackberry were measured under field conditions with a portable system (ADC-IRGA with Parkinson Leaf Chamber). Gas exchange primocane pentifoliate leaflets were similar. Gas exchange rates of leaves along a cane exhibited a quadratic function of leaf position with leaves in lower-mid sections (relative position 0.3 - 0.5) having higher A, TR, WUE, gs than either basal or apical leaves. Leaves subtending fruiting laterals on fruiticanes had higher assimilation than similar age leaves on primocanes but did not differ in Tr, WUE, or gs. Primocanes had estimated dark respiration rates of 0.33mg·dm-1.hr-1, estimated light compensation at 14-20 mol.m-2.s-1, estimated light saturation at 1000-1100 mol.m-2.s-1 with maximum A rates ranging from 24-30 mg CO2.dm-1.hr-1. Measurements were made at field temperatures ranging from 24-35 C. Although temperature response was not measured, correlation indicated that Tr, WUE, and gs were more closely related to temperature than A. Similarly, Tr and WUE were more closely related to gs than A (r = 0.6 to 0.8).

Download Full-text

Photosynthesis and CO2 evolution by leaf discs: gas exchange, extraction, and ion-exchange fractionation of 14C-labeled photosynthetic products

Canadian Journal of Botany ◽

10.1139/b71-171 ◽

1971 ◽

Vol 49 (7) ◽

pp. 1225-1234 ◽

Cited By ~ 84

Author(s):

C. A. Atkins ◽

D. T. Canvin

Keyword(s):

Gas Exchange ◽

Ion Exchange ◽

Gas Analysis ◽

Co2 Evolution ◽

Leaf Discs ◽

Leaf Chamber ◽

Rate Of Photosynthesis ◽

Photosynthetic Products ◽

Exchange Extraction ◽

Analysis System

A leaf chamber is described which allows the measurement of the gas exchange of leaf discs in an open gas analysis system. Pretreatment of the leaf discs with nitrogen and inclusion of moist filter paper in the leaf chamber resulted in rates of photosynthesis that were constant for 40 min and equal to 60 to 70% of the rate of photosynthesis measured in intact leaves. Analysis of the products of 14CO2 fixation from whole leaves and leaf discs and a comparison of the gas exchange under various conditions established that the leaf discs accurately reflected the metabolism of the attached leaves.

Download Full-text

Physiological Responses of Ocimum basilicum, Salvia officinalis, and Mentha piperita to Leaf Wounding

Plants ◽

10.3390/plants10051019 ◽

2021 ◽

Vol 10 (5) ◽

pp. 1019

Author(s):

Konstantinos Vrakas ◽

Efterpi Florou ◽

Athanasios Koulopoulos ◽

George Zervoudakis

Keyword(s):

Gas Exchange ◽

Ocimum Basilicum ◽

Salvia Officinalis ◽

Mentha Piperita ◽

Gas Exchange Parameters ◽

Wide Range ◽

Intact Leaves ◽

Almost All ◽

Exchange Parameters

The investigation about the leaf wounding effect on plant physiological procedures and on leaf pigments content will contribute to the understanding of the plants’ responses against this abiotic stress. During the experiment, some physiological parameters such as photosynthesis, transpiration and stomatal conductance as well as the chlorophyll and anthocyanin leaf contents of Ocimum basilicum, Salvia officinalis, and Mentha piperita plants were measured for about 20–40 days. All the measurements were conducted on control and wounded plants while in the latter, they were conducted on both wounded and intact leaves. A wide range of responses was observed in the wounded leaves, that is: (a) immediate decrease of the gas exchange parameters and long-term decrease of almost all the measured variables from O. basilicum, (b) immediate but only short-term decrease of the gas exchange parameters and no effect on pigments from M. piperita, and (c) no effect on the gas exchange parameters and decrease of the pigments content from S. officinalis. Regarding the intact leaves, in general, they exhibited a similar profile with the control ones for all plants. These results imply that the plant response to wounding is a complex phenomenon depending on plant species and the severity of the injury.

Download Full-text

Gas Exchange Studies of Carboxylation Kinetics in Intact Leaves

Progress in Photosynthesis Research ◽

10.1007/978-94-017-0519-6_54 ◽

1987 ◽

pp. 245-252 ◽

Cited By ~ 10

Author(s):

A. Laisk ◽

O. Kiirats ◽

H. Eichelmann ◽

V. Oja

Keyword(s):

Gas Exchange ◽

Intact Leaves

Download Full-text

Factors influencing the measurement of assimilation and stomatal conductance with the LI-COR 6400XT gas exchange system.

10.1101/494120 ◽

2018 ◽

Author(s):

Daniel LeCain ◽

Sean Gleason

Keyword(s):

Stomatal Conductance ◽

Gas Exchange ◽

Experimental Error ◽

Leaf Age ◽

Time Of Day ◽

Species Variation ◽

Plant Responses ◽

Exchange System ◽

Leaf Chamber ◽

Gas Exchange System

Abstract: Although CO2 and H2O exchange rates are often measured in experiments as indicators of physiological plant responses these gas exchange measurements are prone to large experimental error. Gas exchange equipment and technology have improved greatly over the past two decades which supports scrutinizing current issues of experimental error in measuring plant photosynthesis and stomatal conductance. This report shows results of a greenhouse experiment with the goal of identifying lessor understood sources of experimental error and variation in measurements with the LI-COR 6400XT gas exchange system. A variety of plant types were used to encompass differing species variation. We found significant sources of experimental error in 1) the time for initial adjustment when placing a leaf in the leaf chamber 2) the time-of-day when measuring 3) leaf age 4) having the chamber window full vs. partially full with leaf tissue 5) using a leaf chamber environment that greatly diverges from the whole plant environment 6) differing degree of experimental error depending upon plant species. A situation with multiple contributors to error would result in useless gas-exchange data. Recommendations for minimizing these experimental errors are given.

Download Full-text

Repeated Mechanical Stress from Leaf Cuvette Influences Leaf Gas Exchange

HortScience ◽

10.21273/hortsci.27.5.432 ◽

1992 ◽

Vol 27 (5) ◽

pp. 432-434 ◽

Cited By ~ 3

Author(s):

Thomas E. Marler ◽

Michael V. Mickelbart

Keyword(s):

Stomatal Conductance ◽

Gas Exchange ◽

Mechanical Stress ◽

Leaf Gas Exchange ◽

Mangifera Indica ◽

Mechanical Stimulus ◽

Persea Americana ◽

Long Term Effects ◽

Leaf Chamber ◽

Fixed Set

Long-term effects on stomatal conductance of mechanical stress from repeated clamping of a porometer leaf cuvette to laminae of avocado (Persea americana Miller), carambola (Averrhoa carambolu L.), hibiscus (Hibiscus rosa-sinensis L.), mango (Mangifera indica L.), and sugar apple (Annona squamosa L.) plants were determined under glasshouse conditions. Following 10 weeks of applying the mechanical stimulus seven times during every 4th day to mature leaves, stomatal conductance was lower than for untreated leaves of all species except mango. Similarly, following 10.5 weeks of applying the stimulus one time every 4th day to expanding leaves of avocado, carambola, hibiscus, and sugar apple, stomatal conductance was lower than for untreated leaves of the same age in all species except hibiscus. Carambola and sugar apple were more sensitive to the mechanical stress than the other species. Thus, the indirect effect of leaf chamber clamping on gas exchange should be known before any conclusions are formulated regarding environmental, cultural, or genetic effects on gas exchange. Random leaf samples from a canopy instead of measurements on a fixed set of leaves may be more appropriate for repeated determinations of leaf gas exchange on a set of plants.

Download Full-text