Analyses of ionic compositions of acid rain in the San-in districts and studies on effects of simulated acid rain on growth and physiology of trees.

从1990年4月至1991年12月，对三因地区鸟取大学森林中的雨林的降雨量、雨水的pH值和离子组成进行了连续监测。酸碱度随着SO4离子浓度的升高而降低。研究了模拟酸雨溶液(SO4^&lt；2-&gt；：NO3^-=1：1)对木本植物幼苗生长、干重增长和乙烯释放的影响。用pH 1.6溶液处理落叶松、白榆树和赤松幼苗2个月，可显著降低其生物量。PH值为2.6、3.6和4.6的其他处理对所有树种的干重增长均无显著影响，而在土壤表面喷施3个月的pH 1.6溶液显著降低了盆栽柳杉和钝顶柳杉幼苗的生物组学。研究了硫酸溶液对木本植物幼苗生长、干重增长和植物生长调节剂产生的影响。用5 mM/l溶液(PH2.10)喷施植株茎段2个月，可显著降低日本白桦、白桦、密花白桦、榆树幼苗的生长量和生物量。5 mm/1的溶液也提高了这些物种的乙烯产量。叶面喷施5、0.5、0.05 mM/L溶液可显著降低白桦、白桦、赤松、白桦针叶中的IAA含量。ABA含量不受酸处理的影响。

The amount of precipitation, pH values of rain water, and ionic compositions were continuously monitored from April, 1990 to December, 1991 in the Hiruzen forest of the Tottori University Forests in the San-in districts. The pHs tended to be lower corresponding with the rise Of SO_4 ion. The amount of nss (not from sea salts) -SO_4^<2-> was comparatively high in early winter and in April.Effects of simulated acid rain solutions (SO_4^<2-> : NO_3^- = 1 : 1) on growth, dry weight increment, and ethylene production in seedlings of woody species were investigated. Application of the pH 1.6 solution to the shoot system of plants for 2 months significantly decreased biomass of Larix leptolepis, Ulmus davidian, and Pinus densiflora seedlings. Treatments with other solutions including pH 2.6, 3.6, and 4.6 had no significant effects on dry weight increment of all of these species.Application of the pH 1.6_solution to the soil surface for 3 months significantly decreased the biomics of potted Cryptomeria japonica and Chamaecyparis obtuse seedlings. Dry weight reduction was more drastic in seedlings planted in sand or decomposed granite than in andisol.Effects of sulfuric acid solutions on growth, dry weight increment, and production of plant growth regulators in seedlings of woody species were also investigated. Application of the 5mM/I solution (PH 2.10) to the shoot system of plants with a hand spray for 2 months significantly decreased growth and biomass of C. japonica, C. obtusa, P. densiflora, Betura Platyphylla, and Ulmus americana seedlings. The 5mM/1 solution also enhanced ethylene production in these species. The IAA content in needles or leaves was significantly reduced in ptomeria, Chamaecyparis, Pinus, and Betura by the application with 5, 0.5, and 0.05 mM/l solutions. The ABA content was not affected by acid application.