气孔开闭与锶叶面吸收的相互影响

叶面吸收是核素长距离迁移进入植物的首要方式,研究气孔开闭与核素叶面吸收之间的相关关系具有重要意义。以研究最为广泛的锶(Sr)作为核素代表,以双子叶乔木红叶石楠叶片为研究对象,用脱落酸(ABA)和激动素(KT)调节气孔的开闭,探讨核素离子的气孔吸收作用及叶面核素吸收对气孔开闭的影响。结果表明:Sr对气孔开启有明显的抑制作用,浓度越高抑制效果越明显;在10 mmol/L的Sr溶液中暴露2 h后,气孔开启度仅为-105.18%;气孔开闭对核素吸收存在显著的影响,开启度越高核素叶面吸收越强;72 h时,Sr单位叶面吸收量为9.61μg/cm2,添加20 mg/L ABA后叶面吸收量下降13.1%(8.35μg/cm2),而添加20 mg/L KT后叶面吸收量增加21.6%(11.69μg/cm2)。

On the relation between the foliar uptake of strontium and the stomatal aperture

The given paper is aimed to present the results of its investigation of the relationship between the foliar uptake of the nuclide and the stomatal aperture of the leaves and the effect of the nuclide adsorption on the stomatal opening,in addition to that of the stomatal aperture on the nuclide foliar uptake,respectively and correspondingly.For the said purposes,we have chosen strontium as the model nuclide and the leaves of the common dicotyledonous Photinia fraseri as the sampling ones.In doing so,we have also identified and examined the surface micro-morphology of the samples via the atomic force microscopy and scanning electron microscopy so as to characterize and typify the functional groups via the Fourier infrared spectroscopy.In addition,we have also made an observation examination of the abscisic acid(ABA) and kinetin(KT) with the purpose to regulate the stomatal aperture of the leaves and the opening of the stomata via the Carnot fixation method.The results of our observation and investigation have thus demonstrated that:(1) The leaf surfaces of Photinia fraseri have been found clustered and covered with rough wax crystals,whereas the adaxial surface distributed with more fatty functional groups than in the abaxial surfaces due to the stronger hydrophobicity at its surface.But,in contrast,the abaxial leaf surfaces have been discovered surrounded by stomata with 70 000 stomata per a square centimeter.More exactly speaking,a pore diameter of stomata takes about 16 μm,whereas the opening length occupies about 3.5 μm.And the total area of stomata tends to take about 10％ of the leaf's total surface area;(2) The ABA and KT can be found effective in regulating the stomatal opening and closing,while its opening tends to be inhibited or can be prohibited by adding ABA solution with the negatively linear correlation of stomatal aperture with ABA concentration being found(y =-20.9-0.22x,R2 =0.98).On the contrary,KT has been found with stimulative effect on the stomatal opening,whose stomatal aperture has been found in positively linear relation with the KT concentration(y =14.11 +2.64x,R2 =0.95);(3) Strontium tends to show inhibitory effect on the opening of stomata with more inhibition effect with the increase of its concentration.However,its stomatal aperture can be suppressed to-105.18％ if the leaf were treated with 10 mmol/L strontium solution for 2 hours;(4) With the increase of the stomatal opening,it would be possible for the strontium to get higher foliar uptake.For example,the absorption capacity of Sr on Photinia serrulata can be increased to 9.61 μg/cm2 in 72 hours,whereas the capacity can be reduced to 8.35 μg/cm2 (13.1％) by adding 20 mg/L ABA but heightened by a percentage of 21.6％ (11.69 μg/cm2) by adding 20 mg/L KT.Therefore,the above observation and investigation results we have gained may imply that significant influence can be found on the foliar uptake of strontium by the stomatal movement with a great risk to be brought about to the physical activity of the stomatal leaves.