【作者】 白晓敏；

【导师】 查天山；

【作者基本信息】 北京林业大学 ， 水土保持与荒漠化防治， 2013， 硕士

【摘要】 本试验使用LI-6400测量沙柳(Salix psammophila)、沙蒿(Arlemisia intramongolica)、花棒(Hedysarum scoparium)气体交换与叶绿素荧光参数,以了解其日、季节动态变化规律,探索影响其光合作用的主要环境因子,为提高植物光合生产力提供理论依据。主要研究结果如下：1.沙柳、花棒净光合(Pn)日变化为单峰型曲线,沙蒿Pn日变化曲线既有单峰型曲线又有双峰型曲线。适宜环境条件下,沙柳、沙蒿、花棒Pn峰值分别出现在10：30、11：30、11：30。但严酷的环境条件下,其峰值提前。2.沙柳、沙蒿、花棒Pn季节变化为双峰曲线,花棒次峰不明显。Pn日均最大值沙柳出现在9月上旬,为11.24μmol m-2s-1；沙蒿Pn出现在6月下旬,为14.77μmol m-2s-1；花棒Pn出现在7月上旬,为6.13μmol m-2s-1。3.沙柳蒸腾速率(E)日变化为单峰型曲线,在10：30-14：30之间出现峰值。沙蒿、花棒E日变化同时具有单峰型和双峰型,单峰型曲线峰值出现在11：30,双峰型曲线主峰值出现在9：30,次峰值出现时间不定。4.光响应曲线分析表明沙柳、沙蒿、花棒均具有较宽的光合生态幅和较强的强光适应性。沙柳光能利用效率、固碳能力与生物生产潜力最高,沙蒿次之,花棒最低。5.在试验测定的环境因子中影响沙柳Pn的主要环境因子是水分；影响沙蒿Pn的主要环境因子是温度和大气相对湿度；影响花棒Pn的主要环境因子是温度和光照强度。6.沙柳、沙蒿、花棒的光下最大光量子产量(Fv’/Fm’).PS Ⅱ实际量子效率(ΦPSⅡ)、光化学淬灭(qp)的日变化曲线为“V”型,非光化学淬灭电子淬灭(NPQ)的日变化曲线为单峰型曲线。沙柳、沙蒿相对电子传递速率(ETR)的日变化曲线既有单峰曲线又有双峰曲线,双峰曲线出现在7月中旬、8月中旬。花棒ETR的日变化曲线为单峰曲线。7.沙蒿ΦPSⅡ、qp最大,其光能接受及转化效率最高,能最多的把吸收的光能用于光化学反应中,将更多份额的光能转化为化学能。沙柳次之,花棒最低。沙蒿ETR最大,光合能力最强,花棒次之,但花棒在生长末期光合能力低于沙柳。沙蒿Fv’/Fm’、NPQ均大于其它两种植物,说明沙蒿具有较强的激发能捕获效率,对光强的调节能力较强。沙柳PsII激发能捕获效率较低，但其热耗散能够力比花棒强。以上说明沙蒿对生长地的光环境适应能力最强。更多还原

【Abstract】 Li-6400portable photosynthesis system was used to measure photosynthetic and chlorophyll fluorescence PARameters of Salix psammophila, Artemisia intramongolica, and Hedysarum scoparium. The objectives of this case are to understand their diurnal and seasonal dynamics, and to explore the main environmental factors that influence the PARameters of photosynthesis and chlorophyll fluorescence. The main results were:1. Diurnal changes of net photosynthetic rate (Pn) of Salix psammophila and Hedysarum scoparium showed one-peak curves.That of Artemisia intramongolicahad both one-peak curves and two-peak curves. Under favorable environmental conditions, the peak appeared at10:30,11:30, and11:30for three species (in an order that appeared above), respectively. Under harsh environmental conditions, the peak appeared earlier.2. Seasonal change of net photosynthesis rate of Salix psammophila, Artemisia intramongolica, Hedysarum scoparium showed two-peak curves, but the secondary peak of Hedysarum scoparium were not obvious. The maximum Pn of Salix psammophila was11.24μmol m-2s-1and appeared at mid-September. The maximum Pn of Artemisia intramongolicawas14.77μmol m-2s-1and appeared at late September. The maximum Pn of Hedysarum scoparium was6.13μmol m-2s-1and appeared at early July.3. Diurnal changes of transpiration rate (E) of Salix psammophila were one-peak curves. The peak was detected between10:30-14:30. That of Artemisia intramongolica and Hedysarum scoparium had both one-peak curves and two-peak curves.The peak of one-peak curves appeared at11:30and the main peak of two-peak curves appeared at9:30.4.The light response curves indicated that all the three species had wide photosynthetic ecological amplitude and strong adaptability to high Light intensity. Salix psammophila had the highest light use efficiency, carbon sequestration capacity and biological production potential, followed by Artemisia inframongolicaand Hedysarum scoparium.5.The major environmental factor influencing net photosynthetic rate of Salix psammophila was moisture content. The main environmental factors that affected Artemisia intramongolicawere temperature and relative humidity. The major environmental factor influencing net photosynthetic rate of Hedysarum scoparium was temperature and light intensity.6.Diurnal changes of PS Ⅱ maximum efficiency (Fv’/Fm’)、the efficiency of photosystemⅡ photochemistry (OPSⅡ),photochemical quenching (qp) of Salix psammophila, Artemisia intramongolica, Hedysarum scoparium were all "V" type curves. Diurnal changes of Nonphotochemical quenching (NPQ) of three species were one-peak curves. Diurnal changes of electron transport rate through PSⅡ (ETR) of Salix psammophila and Artemisia inframongolicahad both one-peak and two-peak curves. Two-peak curves were detected at mid-July and mid-August. Diurnal changes of ETR of Hedysarum scoparium were one-peak curves.7. Artemisia intramongolicahad the maximum ΦPSⅡ and qp, which indicated the highest efficiency of achieving and altering light energy. That means Artemisia intramongolicacan allocate more light energy for photochemical and can alter more light energy into chemical energy. Salix psammophila followed Artemisia intramongolicaand was higher than Hedysarum scopariumwere. Artemisia intramongolicahad the highest photosynthetic capacity with the largest ETR. The photosynthetic capacity of Hedysarum scopariumwere was lower than Artemisia intramongolicabut was higer than Salix psammophila. At later growth stage, photosynthetic capacity of Hedysarum scopariumwere was lower than Salix psammophila. Highest Fv’/Fm’ and NPQ indicated Artemisia intramongolicahad the highest efficiency of capturing excitation energy and had the highest ability to regulate light energy. Salix psammophila had a lower efficiency of capturing excitation energy than Hedysarum scopariumwere, but had a higher ability to regulate light energy. It was concluded that Artemisia intramongolicaadapted to the dry environment best.更多还原