Portal de Periódicos da CAPES

Studies on the Mechanism of Injurious Effects of Toxic Gases on Crop Plants : XII. On the characteristic in the growth and grain production of rice plant in air pollution area (Yokkaichi city), and the significance as the indicator plant for monitering of air pollution

1975; Crop Science Society of Japan; Volume: 44; Issue: 1 Linguagem: Inglês

10.1626/jcs.44.74

1349-0990

Tetsuro Taniyama, Kazuo SAWANAKA,

Plant responses to elevated CO2

Air pollution in Yokkaichi city is a typical pollution which is caused by the large amount of emission from the steam power installation chiefly using heavy oil, refineries, and many petrochemical factories. As the percentage of heavy oil in fuel is very high, the most serious trouble is sulfur oxides. During the period of May to September when rice plant or other summer crops are grown, the air pollution is brought on the region of paddy around the city. The present study was conducted to clarify the relations between dry matter and grain production in the rice plant, and sulfur oxides in the air of Yokkaichi area. Since 1958, when the first petroleum combinate was established and began to work actually, the grain production of rice plant in Yokkaichi area decrcased continuously up to date. The citizens there began to complain of asthmatic disease, "Yokkaichi Asthma, " which was caused by the sulfur oxides in an air. Author has discussed about the significance as the indicator plants for monitering of air pollutions through clarifying the relation between the patient number of Yokkaichi Asthma and decrease of grain production of rice plant. The results obtained are summarized as follows: 1. The growth and development of rice plant was inhibited by sulfur oxides in Yokkaichi area. The leaf age, number of stems and plant height were smaller in Yokkaichi city than in Tsu city (control plot). 2. The expansion of leaf area and leaf dry weight in Yokkaichi city intreased more than in Tsu city, but, with the progress of growth, those in Tsu city exceeded those in Yokkaichi city. The degree of decrease was larger in dry weight of stems than in that of leaves. Especially the dry weight of roots at the eary growing stage was severely inhibit by air pollution. 3. Tillers that emerged late were observed numerously in Yokkaichi city. The higher concentration of sulfur oxides in an air, the later heading time. The grain production was lower in Yokkaichi city than in Tsu city, and the percentage of decrease in Yokkaichi city was by 35% in a maximum. 4. Of yield components, number of panicles per hill was affected most remarkably by air pollution following percentage of 1, 000 kernels. The relation between total dry weight or grain yield and concentration of sulfur oxides showed high significant correlation. 5. As a typical visible injury by sulfur oxides on the leaf or leaf sheath, through growing period was not observed, the damage of rice plant seems to be due to the invisible injury. The percentage of decrease in the area of the air pollution at Yokkaichi was 50% in total dry weight and 35% in the grain yield. 6. The decrease of grain production of rice plant has occured since 1958, when the first petroleum combinate was established and began to work actually, the damage was most severe in 1961 and 1965. The relation between percentage of grain production in Yokkaichi area and the number of asthmatic disease which is called "Yokkaichi Asthma." showed a significant correlation. The Yokkaichi Asthma was observed at five years after the decrease of grain production occured in 1958, From this it is extremely important that the indicator plants for monitering of air pollution as the evil omen of effect to human being and to the decrease in production of crop plant are utilized