利用同位素研究苗木在不同土壤中对两种磷源的吸收

On seedling's uptake iron phosphate in several soils with ^(32)P labeledphosphate.

作者利用同位素示踪和苗木放射性自显影技术,用^(32)P制备的标记铁磷和过磷酸钙分别施用于杉木、银杏、马尾松、柏木和黑松等苗木的根际土壤中;分别采用红壤、黄壤和石灰性土壤进行试验。经两年试验,结果表明:铁磷是能够被吸收利用的磷源,只不过吸收利用的速度很侈。在施用标记过磷酸钙63天内测定苗木对^(32)P的吸收动态时发现,磷在苗木组织中有不断积累的趋势;未见磷被“固定”而逐渐降低其有效性。施标记肥63天时,银杏从铁磷中吸收的^(32)P为从过磷酸钙中吸收的^(32)P的4.1％(红壤中)。在3类不同土壤中的试验均有相类似的趋势。

With the technique of isotope tracer and autoradiograph, we obtained the following main results: 32P-labeled iron phosphate could be uesd by the seedlings of Pinus massoniana Lamb., Cunninghamia lanceolata Hook., Cupressus funebris Endl., and Ginkgo biloba Linn. as a phosphorous source, although the amounts of phosphorus absorbed from iron phosphate were quite small. The amounts of phosphorus absorbed by the plants both from 32P-labeled calcium superphosphate and from iron phosphate were found to be constantly on the increase during two experimental periods in 1985 and 1987. The ratio of iron phosphate to calcium superphosphate, which absorbed by Ginkgo biloba Linn., reached up to 4.1 per cent at the 63th day after fertilization in 1987. The results indicated that even if soluble phosphate was reduced to insoluble iron phosphate in soils, the latter could be used by the plants described above.