報告書番号

U01028

タイトル（和文）

ウメ，ヤマザクラ，コナラ，スダジイおよびヒノキの生育におよぼす二酸化硫黄とオゾンの単独および複合影響

タイトル（英文）

Effects of sulfur dioxide and/or ozone on the growth of Prunus mume, Prunus jamasakura, Quercus serrata, Castanopsis cuspidata and Chamaecyparis obtusa

概要 （図表や脚注は「報告書全文」に掲載しております）

ウメ，ヤマザクラ，コナラ，スダジイ，ヒノキを，4段階のSO2（浄化大気，5，10，20ppb）と3段階のO3（浄化大気，外気1.0倍，1.5倍）に単独および複合で1年半にわたって暴露し，可視害発現，落葉量，生長（樹高，幹直径，乾重量）におよぼす影響に関する樹種間差異を調べた。その結果，（1）SO2に対する感受性は，ウメ・ヒノキでは中庸，ヤマザクラ・コナラ・スダジイでは抵抗性，（2）O3に対する感受性は，ヤマザクラ・スダジイでは高感受性，ウメ・ヒノキでは中庸，コナラでは抵抗性，（3）SO2 とO3 の複合に対する感受性は，ヒノキとコナラでは汚染物質単独の場合より高くなり，それぞれ高感受性と中庸を示した。以上のことから，現在和歌山県田辺市や周辺域で観測される現状の濃度では，5樹種におよぼすSO2単独の影響は極めて小さいこと，ウメではSO2とO3の複合影響も極めて小さいことが明らかとなった。

概要 （英文）

Decline of Japanese apricot (Prunus mume Sieb. et Zucc. cv. Nanko) has occurred and expanded in and around Tanabe City, Wakayama Prefecture, Japan. One of causes of its decline is pointed out to be linked with gaseous air pollutants. However, no information is available for assessing the effects of sulfur dioxide (SO2) and/or ozone (O3) on the growth of Japanese apricot and other tree species naturally grown in and around the city. Therefore, in the present study, the exposure experiment using the open-top chamber systems was conducted to assess the interspecific variation in sensitivity among five tree species (Prunus mume Sieb. et Zucc. cv. Nanko, Prunus jamasakura Sieb. ex Koidz., Quercus serrata Thunb., Castanopsis cuspidata Schottky var. sieboldii Nakai and Chamaecyparis obtusa Sieb. et Zucc) to SO2 and/or O3, based on the foliar visible injury (including the defoliation) and the response of growth (heoght, stem diameter and dry weight). The experimental design was four levels of SO2 (filtered air with activated-charcoals [FA], FA added at a constant concentration of 5, 10 and 20 ppb [24 hour day -1]) by three levels of O3 (FA, FA added in proportion to 1.0 and 1.5 times the ambient air [AA] in O3 [24 hour day -1]) for a total of twelve treatments. Exposure to pollutants was conducted for two growing seasons (from May in 1998 to November in 1999) at the Akagi Testing Center of CRIEPI at an elevation of 540 m a.s.l. on the south slope of Mt. Akagi, Gunma Prefecture. The concentrations of SO2 in 5 ppb SO2 treatment and O3 in 1.0x O3 treatment were almost same as those monitored in and around Tanabe City. The sensitivities to SO2 and/or O3 were classified into sensitive, intermediate and tolerant groups: i) Prunus mume and Chamaecyparis were intermediate, and the other three species were tolerant to SO2, ii) Prunus jamasakura and Castanopsis were sensitive, Prunus mume and Chamaecyparis were intermediate, and Quercus as tolerant to O3, iii) the sensitivity to the combination of both pollutants was higher than to the pollutant alone for Chamaecyparis and Quercus (sensitive and intermediate respectively), in contrast with that being the same as to O3 alone for Prunus mume, Prunus jamasakura and Castanopsis. These results indicated that (i) the current ambient concentration of SO2 (2 to 4 ppb for 24 hour mean) is low for inducing apparent growth reduction in the five tree species, (ii) the combined effect of SO2 and O3 at the current ambient level is unlikely to be linking with wide spread growth retardation of Japanese apricot in and around Tanabe City.

報告者

キーワード