沙埋对白刺表型可塑性的影响

Effects of Sand Burial on Phenotypic Plasticity of Nitraria tangutorum

[目的]为研究沙埋对白刺形态、生物量分配及光合特性的表型可塑性的影响,[方法]对扦插白刺,进行0、5、10、15 cm沙埋处理,待生长季结束后,收集数据进行统计分析。[结果]表明:随着沙埋深度的增加,(1)株高、15 cm基径呈减小趋势,不定根长与不定根直径呈先增大后减小的趋势。当沙埋深度为0、5、10、15 cm时,植株的株高依次为62.82、55.90、52.38、49.24 cm,15 cm处基茎依次为2.79、2.48、2.39、2.07 mm,叶面积依次为477.81、214.38、247.90、112.91 cm^2,叶片数依次为700.2、334.40、344.00、216.20片,不定根数依次为6.40、3.80、2.80、3.40根,不定根长依次为10.19、11.54、13.92、7.62 cm,不定根直径依次为1.51、1.95、1.65、1.19mm;(2)枝与叶生物量、总生物量呈减小趋势,而地下部分生物量呈先增大后减小的趋势,地上生物量/地下生物量呈先减小后增大的趋势。当沙埋深度为0、5、10、15 cm时,植株的枝生物量依次为6.29、4.20、3.09、2.75 g,叶生物量依次为3.93、2.52、3.31、1.28 g,总生物量依次为10.81、7.53、7.41、4.30 g,地下部分生物量依次为0.59、0.81、0.59、0.28 g,地上生物量/地下生物量依次为17.32、8.30、10.85、14.39;(3)净光合速率、蒸腾速率和气孔导度的日均值呈依次增加的趋势,如沙埋深度为0、5、10、15 cm时,净光合速率的日均值依次为8.06、9.39、9.72、11.25μmol·m^(-2)·s^(-1),蒸腾速率的日均值依次为5.56、6.70、6.77、7.61 mmol·m^(-2)·s^(-1),气孔导度的日均值依次为0.28、0.31、0.31、0.36 mol·m-2·s-1。(4)沙埋深度5.10 cm白刺的叶绿素a、叶绿素b、叶绿素(a+b)含量与对照组0 cm的差异不显著,当沙埋深度为15 cm时,叶绿素含量显著增大,但叶绿素a/b值的变化不显著。[结论]白刺形态、生物量分配以及叶绿素含量对不同沙埋深度的可塑性较强,当沙埋深度为15 cm时,光合指标对沙埋才会产生显著差异。

[Objective]To understand the effect of sand burial on the phenotypic plasticity of Nitraria tangutorum, [Method]The cutting shoots of N.tangutorum were treated by sand burial under different depths （0,5,10,and 15 cm）and then to analyze the data collected.[Result]（1 ）With the increase of sand burial depth,the plant height,15 cm stem diameter,leaf area,the amounts of leaf and adventitious root decreased,and the length or di-ameter of adventitious root increased at first and then decreased.It was found that when the sand burial depths were 0,5,10,and 15 cm,the heights of the plant were respectively 62.82,55.90,52.38,and 49.24 cm,the 15 cm stem diameters were respectively 2.79,2.48,2.39,and 2.07 mm,the leaf areas were 477.81,214.38,247.90, and 112.91 cm^2,the amounts of adventitious root were respectively 6.40,3.80,2.80,and 3.40,the lengths of adventitious root were respectively 10.19,11.54,13.92,7.62 cm,the diameter of adventitious root were respec-tively 1.51,1.95,1.65,and 1.19 mm.（2）With the increase of sand burial depth,the above-ground biomass and the total biomass decreased,and the length,diameter of adventitious root and the below-ground biomass in-creased at first and then decreased,the biomass of above-ground/the below-ground biomass first decreased then in-creased.It was found that when the sand burial depths were 0,5,10,and 15cm,the branch biomasses were re-spectively 6.29,4.20,3.09,and 2.75 g,the leaf biomasses were respectively 3.93,2.52,3.31,and 1.28 g, the total biomasses were respectively 10.81,7.53,7.41,and 4.30 g,the below-ground biomasses were respec-tively 0.59,0.81,0.59,and 0.28 g,the biomass of above-ground/the below-ground biomass respectively is 17.32、8.30、10.85、14.39.（3）The daily averages of net photosynthetic rate,transpiration rate and stomatal con-ductance of N.tangutorum increased gradually.It was found that when the sand burial depths were 0,5,10,and 15 cm,the daily averages of net photosynthetic rate were respectively 8.06,9.39,9.72,and 11.25 μmol·m^-2· s^-1,the daily averages of transpiration rate were respectively 5.56,6.70,6.77,and 7.61 mmol·m^-2·s^-1,the daily averages of stomatal conductance were respectively 0.28,0.31,0.31,and 0.36 mol·m^-2·s^-1.（4）Com-pared with the CK,the difference of chlorophyll contents of N.tangutorum was not significant.When the depth was 15 cm,the chlorophyll contents of N.tangutorum increased significantly,but the differences of the ratio of the chlo-rophyll a and Chlorophyll b were not significant.[Conclusion]The phenotypic plasticity of morphology,biomass al-location and photosynthesis of N.tangutorum were greater under different sand burial depth,and when the sand burial depth was 15 cm,the differences of photosynthetic parameters of N.tangutorum responded to different sand burial depth were significant.