Physiological biochemical changes accompanying pollination in orchid flowers II Respiration, catalase activity, and chemical constituints英文电子书.pdf

PHYSIOLOGICAL AND BIOCHEMICAL CHANGES ACCOM- PANYING POLLINATION IN ORCHID FLOWERS. II. RESPIRATION, CATALASE ACTIVITY, AND CHEMICAL CONSTITUENTS TSUNG-HSUN T. HSIANG1 (WITH TWO FIGURES) Received September 11, 1950 In a previous paper of this series (19), data have been presented to show that pollination in orchid flowers brings about considerable changes in their water balance. The present paper deals with the change in respiratory ac- tivity, catalase activity, and chemical constituents as consequences of polli- nation and auxin treatment. The general methods used in sampling and treatment of flowers are essentially the same as that earlier described (19). A general conclusion, based on all experimental facts presented in both papers, is also given here. Respiration WHITE (35) noted an increase of respiratory rate and also of respiratory quotient after pollination in a number of plant species. A critical examina- tion of her data, however, would seem to show that the respiratory quotient was unusually low for the non-pollinated plants, indicating that some con- stant errors might have been involved. Moreover, in most of the plants she used, fertilization is known to follow pollination more or less closely. It is therefore not safe to attribute the observed effects, if valid, to pollination alone. Further work is needed on the effect of pollination on respiration. In the work reported here respiration was measured as the amount of 02 taken up per unit of time per unit of dry weight. A Warburg respirometer of the constant volume type was employed. All experiments were run at 250 + 0.20 C. Preliminary study showed that when tissue sections were floated on phosphate buffer solution at a pH