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牧草叶片的蒸腾和过度生长是一膨压控制的过程。膨压的保持不可避免地要联系到溶质的浓度和渗透势。用大部分叶片的膨压(ψ_)预测气孔阻力(R_)的经验方程对建立草地管理的计算机模型是很有用处的。在生长室内进行的研究是为了定量地确定草地早熟禾(Poa PratensisL.CV A—34)R_与ψ_之间的关系。施氮、钾和灌水频率对大部分叶片满膨压时的渗透势(ψ_(100))和质外体水分(AWF)的影响用湿度计的方法也进行了研究。试验处理包括两个施氮和钾水平及两个灌水频率。R_S和ψ_之间的关系可用一指数函数来描述。其预测方程为:R_=581+2500e~(-6.99ψ_)(r~2=0.69),式中以和R_S的单位分别为MPa和s·m~(-1)。增加灌水间隔时间(由1d增为5d)不影响(ψ_(100))。每天灌水一次,每30d增加氮肥施用量(由35增加到175kg/hm~2)(ψ_(100))增加了0.22MPa,而在相同时间内增加钾的施用量(由17.5增加到175kg/hm~2)(ψ_(100))降低了0.20MPa。若5d灌一次水,改变氮钾施用量不影响(ψ_(100))。将灌水时间由1d增为5d,AWF由22%下降为12%。研究结果表明,施氮钾的交互作用对草地早熟禾所有叶片渗透性溶质的浓度有显著影响。
The transpiration and overgrowth of pasture leaves are a turgor-controlled process. The maintenance of turgor inevitably involves the solute concentration and osmotic potential. Predicting the stomatal resistance (R_) empirical equation with most of the blade turgor (ψ_) is very useful for establishing a computer model of grassland management. The study conducted in the growth chamber was designed to quantitatively determine the relationship between R_ and ψ_ for Poa Pratensis L.CV A-34. The effects of nitrogen, potassium and irrigation frequency on the osmotic potential (ψ_ (100)) and apoplast moisture (AWF) at the time of most turgor inflating were also studied using a hygrometer. The experimental treatments included two nitrogen and potassium levels and two irrigation frequencies. The relationship between R_S and ψ_ can be described by an exponential function. The prediction equation is: R_ = 581 + 2500e ~ (-6.99ψ_) (r ~ 2 = 0.69), where R_S and R_S are respectively MPa and s · m ~ (-1). Increasing the irrigation interval (from 1d to 5d) did not affect (ψ_ (100)). Irrigation every day increased the amount of nitrogen application (increased from 35 to 175 kg / hm ~ 2) (ψ_ (100)) by 0.22 MPa every 30 days, and increased the amount of potassium applied from 17.5 to 175 kg / hm ~ 2) (ψ_ (100)) decreased by 0.20MPa. If 5d irrigation water, to change the amount of nitrogen and potassium does not affect the application (ψ_ (100)). The irrigation time increased from 1d to 5d, AWF decreased from 22% to 12%. The results showed that the interaction of nitrogen and potassium had a significant effect on the concentration of osmotic solutes in all the leaves of Kentucky bluegrass.