In a previous paper the author presented a new simple volumeter for measurement of photosynthesis and respiration rates with the use of a low power microscope. This was improved to permit the measurement without the microscope. Five to seven volumeters, one being thermobarometer, were used simultaneously. Photosynthesis rate is measurable within about 10minutes, and respiration rate within about 30minutes. This apparatus is useful in measurements not only indoors but also outdoors. Presented in this report are the data obtained from measurements made indoors and outdoors on 32 species of plants; that is 1 aquatic, 3 marine and 28 land plants. The apparent photosynthesis rates are generally larger than those previously observed under near-natural conditions. This may be due to the high concentration of CO2 (2.7%), high temperature (30°), and also the use of cut leaf strips permitting large gas exchange through the cut surface. In a leaf of Ficus elastica the photosynthesis rate was somewhat higher at the more apical and near-margin parts of the leaf than at the basal and near-midrib ones, respectively. No such difference was seen on the respiration rate.
The chromosome numbers of the five species and one variety of Hosta (H. plantaginea, H. tokudama, H. kikutii, H. crisupla, H. longipes and H. kikutii var. yakusimensis) were 2n=60. The 60 chromosomes were classifiable into 30pairs. The karyotypes of the above species were as follows: The 30pairs of one species and one variety (H. crisupla and H. kikutii var. yakusimensis) could be classified into four pairs of large chromosomes, two pairs of medium ones, and 24 pairs of small ones. The karyotypes of the other four species were as follows: In three of these species (H. plantaginea, H. tokudama and H. kikutii), the chromosomes could be classified into four pairs of large chromosomes, three pairs of medium ones, and 23 pairs of small ones. In the remaining one species (H. longipes), there were four pairs of large chromosomes, four pairs of medium ones and 22 pairs of small ones. H. kikutii and H. kikutii var. yakusimensis seem, judging from their karyotypes, to have both derived from H. montana.