铁尾矿基质下刺槐、紫穗槐光合及生长特性的研究

Photosynthesis and growth characteristics of Robinia pseudoacacia and Amorpha fruticosa cultured in iron tailings matrices

为探讨刺槐、紫穗槐对铁尾矿的适应特性,采用全砂和半土半砂基质改良盆栽试验,对刺槐和紫穗槐在全砂和半土半砂基质条件下的光合生理特性、高生长量、地径生长量和生物量进行了测定,结果表明:刺槐和紫穗槐在全砂和半土半砂基质条件下的净光合速率(Pn)、气孔导度(Gs)、胞间CO2浓度(Ci)均未出现显著性差异,但在全砂条件下刺槐Pn有午休趋势;刺槐和紫穗槐在全砂和半土半砂基质条件下株高、地径生长量、地下生物量和根冠比(T/R)均未达显著差异水平,但是地上生物量在不同基质条件下差异显著,与全砂处理相比,半土半砂条件下地上生物量较高,根冠比较小。全砂处理将资源更多的分配到根系的生长。不同基质条件下刺槐生物量远大于紫穗槐生物量,刺槐的光合午休和根冠比的调整是其对全砂条件的响应策略。

The photosynthetic characteristics,height growth,diameter growth and biomass of Robinia pseudoacacia and Amorpha fruticosa were explored using pot experiments with two kinds of matrices including iron tailings and iron tailings added with soil half and half.The results showed that the net photosynthetic rate（Pn）,stomata conductivity（Gs）and stomata CO2concentration（Ci）of R.pseudoacaciaand A.fruticosa were not significantly different between the two matrices.However,the midday depression occurred during the diurnal changes of photosynthesis of R.pseudoacaciain iron tailings matrix.The height growth,diameter growth,roots biomass and root-shoot ratio of R.pseudoacacia and A.fruticosain the matrices were not significantly different,while their stem and leaf biomass in two matrices were significantly different.The stem and leaf biomass of iron tailings added with soil half and half matrix was higher,while its root-shoot ratio was lower than that of iron tailings matrix.The nutrition in iron tailings matrix was going to be mainly used for a plant rooting.The biomass of R.pseudoacacia was far greater that that of A.fruticosa.It was an adaptation response to iron tailings matrix via adjusting its midday depression and root-shoot ratio in R.pseudoacacia.