Applications In Plant Sciences Research Articles

Photoacoustic measurements: application in plant science

By means of the photoacoustic effect light-induced heat can be detected, which is produced during non-radiative de-excitation following absorption of light. This paper gives an overview of the current knowledge of photoacoustic measurements. First, the principle of detection and the different instrumentations are outlined in general. Then the applications of photoacoustic measurements in plant science and in particular in photosynthesis research are described in detail, ( a ) The induction kinetics of intact leaves at high modulation frequencies (where the signal is only determined by heat production) are contrasted with those at low modulation frequencies (where the signal can be determined by photosynthetic oxygen evolution superimposed on the heat production). Examples for ( b ) the determination of time constants and for ( c ) the measurement of the time delay between the excitation and the detection of the signal (phase) are given. Finally, ( d ) photoacoustic spectra are described. These can be used to determine the pigment composition, the depth profile, the efficiency of energy transfer and the pigment activity of a sample.

Atomic Energy Program

The first one-third of the Atomic Energy Commission's most recent report to Congress, submitted at the end of January, contains a summary for the last half of 1951 of those major activities in the atomic energy program which “can be publicly reported without hazard to the national security,” together with a condensation of the AEC's 1951 financial report. The next third of the report, entitled “Atomic Energy and its Applications in Plant Science,” reviews the effects of radiation on plants, isotope research applications, and photosynthesis and biosynthesis of tagged compounds. The final section of appendices is the usual collection of miscellaneous items and tables concerning the Commission, its organization and activities, and related matters.