低剂量La(Ⅲ)与酸雨对大豆幼苗生长及光合作用的复合影响

为探索稀上元素镧与酸雨对大豆幼苗生长和光合作用的复合影响,以大豆幼苗为试材.采用水培法培养,模拟酸雨和镧处理试材.结果表明,在酸雨(AR_1/pH=3.0,AR_2/pH=4.0,AR_3/pH=5.0)单独作用下,各项生长指标均低于对照组,呈现明显的剂量-效应关系;在稀士La(RE_1/20 mg·L~(-1),RE_2/60 mg·L~(-1),RE_3/100 mg·L~(-1))单独作用下,生长指标呈现明显的"低促高抑"规律.RE+AR复合作用影响下,RE_1和AR复合对大豆幼茵生长抑制程度低于AR单独作用,表现为拮抗效应,RE_2、RE_3与AR对大豆幼苗的复合影响表现为协同作用.大豆幼苗的Chl含量和P_n,与其他乍长指标呈现相似的变化规律,研究表明AR、RE及AR+RE对植物光合作用的影响是其影响植物生长的主要因素之一.

On the combined effects of the low density La(Ⅲ) and acid rain on the growth and photosynthesis of soybean seedling

The paper is to present our experimental results on the combined effects of the low density La (Ⅲ) and acid rain on the growth and photosynthesis of soybean seedlings. For our research purpose, we carried out an exploratory experiment, in which soybeans were cultivated under the laboratory conditions by using water culture as the experimental materials with our study focus on disclosing the combined effects of growth and photosynthesis on the soybean seedlings of low density of La and acid rain. The final results of our experiments show that under the stress of the effect of the acid rain alone (for example, AR_1/pH 3.0, AR_2/pH 4.0, AR_3/pH 5.0),the growth of soybean seedlings would be inhibited with the degree of inhibition lasting till the pH value of AR began to fall. And, of RE_1(20 mg· L~(-1)) were used to promote the soybean seedlings growth, it was found that RE2(60 mg· L~(-1)), RE3(100 mg· L~(-1)) would begin to inhibit the growth of the seedlings gently. The degree of inhibition to the growth was found higher if the concentration of RE solution was made greater as the degree of inhibition to the growth in the treatment of RE_3 (100 mg· L~(-1)) was made higher than that of RF_2 (60mg· L~(-1)). Moreover, the inhibition to the growth was found reduced under the combined treatment of RE1 and AR than that in AR or RE1treatment alone. Nevertheless, the combined treatment of RF2, RE3and AR tend to have a combined influence in the form of a concerted effect. That is to say, the content of the chlorophyll and the photosynthetic rate tend to alter in a much similar way to the growth index.It indicates that, though acid rain declined, the chlorophyll content and photosynthetic rate still follow the dose-effect relationship, and the rare earth content in the soil still affects the two indexes in response to the concentration effect. In spite of this, RE_1 and AR combined treatment prove to be antergie in nature, with the RE_2, RE_3 and AR combined treatment being a synergie one. Just as what the assimilation is expected to appear, it may have a direct effect on the biomass. Thus, it can be concluded that the effect of AR and RE on the photosynthesis of the plants turns out to be one of the main factors that affect the plants growth. Though the experiment mentioned was over for the moment, there still remain much more other aspects to be studied further.