燕山南部花粉散布特征研究表明，空气中的花粉反映的是植物花期的季节性变化；表土花粉是植物多年花粉散布的混合；冲积物花粉与空气中和表土花粉显著不同，是取样点上游表土花粉的混合，与取样点周围植被关系较小。因此，根据冲积物花粉恢复古植被，反映的是整个流域的植被面貌，而不是某一点的植被特征。

滦河流域及周边地区空气中的花粉组合基本上反映了当地的植被面貌，与植物的花期相对应，乔木植物的花期多在春季，草本植物的花期多在夏秋季，该地冬季基本上无植物开花，冬季空气中的花粉应是当年或多年春、夏、秋季散落在地上又被风吹到空气中的表土花粉和一些外来花粉;表土花粉随海拔高程的降低依次出现山地草甸、针阔混交林或以针叶树为主的针阔混交林、山地灌草丛、滨海平原草甸和滨海草甸或滨海盐生草甸的等5个花粉组合带，分别为蒿(Artemisia)–唐松草(Thalictrum)–松(Pinus)–桦(Betula)孢粉组合带、松–桦–栎(Quercus)–蒿孢粉组合带、藜科(Chenopodiaceae)–蒿–禾本科(Gramineae)–中华卷柏(Selaginellasinensis)孢粉组合带、藜科–蒿–菊科(Com-positae)–香蒲(Typha)孢粉组合带和藜科–蒿–莎草科(Cyperaceae)–禾本科孢粉组合带；由于花粉在河水中是以悬移质颗粒被搬运，因此在不同时期沉积物花粉组合存在着一定的差异，其中洪水期间河水对孢粉的分选作用最为明显。

In order to investigate the indication of major pollen types to source plants, 39 surface pollen samples are collected from 39 plant communities. The results show that diversity of pollen assemblages presents in different communities. Chenopodiaceae pollen percentages are highest in Kalidium communities and Ceratoides communities (higher than 45%, average is 63.4%), but high Ephedra pollen percentages (higher than 3.3%, average is 16.5%) in Ceratoides communities make it distinguished from Kalidium communities. Artemisia pollen percentages (more than 50%) are much higher than Chenopodiaceae (less than 35%) in Artemisia Communities. Nitraria pollen percentages (higher than 2%, average is 13.6%) are highest in Nitraria communities compared with those in other community patterns. Tamariceae pollen percentages (higher than 2%, average is 8.6%) are highest both in Tetraena and Reaumuria communities compared with those in other community patterns. But in Reaumuria communities, Artemisia pollen percentages are higher than Chenopodiaceae with some other pollen types such as Gramineae, Compositae, Leguminosae; on the contrary, in Tetraena communities, Artemisia pollen percentages are less than Chenopodiaceae with few other pollen types. Calligonum pollen only appears in Calligonum communities (higher than 2%，average is 5%). The results of cluster analysis (CLA) and detrended correspondence analysis (DCA) show that the pollen indication to source plants can be reflected by association indices (A), over-representation indices (O), under-representation indices (U), R-value, the average pollen percentages where parent plants are absent (Xa) and the average pollen percentages where parent plants are present (Xp). Zygophyllum, Calligonum, Tetraena, Tribulus and Tamariceae can indicate source plants very well, owing to high A scores. Artemisia, Chenopodiaceae and Gramineae have high R-values, and Nitraria, Cruciferae and sedum have high O scores, so they are over-represented types, but the higher Xp and the lower Xa values make that these pollen types can also indicate source plants moderately. Allium, Leguminosae, Roseceae, Pedicularis and Compositae have low A scores (less than 0.5), high O and/or U scores, so they cannot indicate source plants clearly. Some other pollen types, such as Pinus, Picea, Betula, Quercus, Ulmus, Ephedra, Elaegnaceae, Ranunculaceae, Caryophyllaceae, Polygonaceae, Saxifragaceae, only appear in pollen assemblages, so their indication cannot be decided. Just like the pollen percentage ratios of Artemisia and Chenopodiaceae (A/C), the ratios of Ephedra and Artemisia (E/A), Nitraria and Ephedra (N/E) can also indicate the aridity of environment. In typical desert communities, A/C ratios are less than 0.5, E/A ratios are more than 0.1, and N/E ratios are less than 1. In steppe desert, A/C ratios are 0.5-2, E/A ratios are less than 0.1, and N/E ratios are more than 1.

中国北方森林植被68个表土花粉样品中，主要花粉类型联合指数(A)、超代表性指数(O)、低代表性指数(U)、R值、植被不存在时花粉百分比最大值(Xa)和平均值(Ma)、植被存在时花粉百分比最大值(Xp)和平均值(Mp)的计算表明：胡桃、青檀、禾本科、菊科、莎草科、皂荚等A值较高，O值及U值均较低，对植被指示明显，为适中代表性类型；云杉、冷杉、栎、鼠李、沙枣、落叶松、榆、杨、黄栌、花椒、木犀科、绣线菊、毛茛科、榛等，尽管A值和O值大于0.5，但Xa远低于Mp，R值小于1，对植被指示意义较明显，属低代表性类型；桦、松、蒿、藜科等，A值适中，O值和R值较高，U值较低，但Xa，Xp和Ma值较高，属超代表性类型，对植被有一定的指示意义；其他花粉类型对植被指示性不明显或需进一步研究。花粉百分比与植物盖度关系研究表明，多数在森林中建群或为优势成分的乔木花粉与母体植物呈显著线性相关关系，森林植被中的伴生乔木、灌木和多数草本花粉与植物盖度无明显的线性相关关系。松花粉30%以上，可能有松林存在；云、冷杉林中云杉、冷杉花粉高于20%，无云杉植物存在时云、冷杉花粉低于5%；落叶松林中落叶松花粉低于20%，落叶松在植被中不占优势时花粉百分比低于5%，周围植被无落叶松存在时花粉百分比多低于1%；桦木林中桦树花粉高于40%，无桦属植物存在时桦属花粉多低于5%；栎树林中栎属花粉百分比高于10%，无栎属植物存在时栎属花粉多低于1%；鹅耳枥林中鹅耳枥林花粉低于15%，无鹅耳枥植物存在时鹅耳枥花粉多低于1%；杨树纯林中杨树花粉百分比约0~5%，杨属与其他阔叶树混交时杨花粉不易被记录到；胡桃楸纯林中胡桃花粉所占百分比约为25%~35%，无胡桃属植物存在时胡桃花粉低于1%；青檀林中青檀花粉低于15%，无青檀属植物存在时青檀花粉也不出现；榆树林中榆树花粉约8%~20%，榆树与其他阔叶树混交时榆树花粉低于1%。

Qinghai-Tibetan Plateau is one of the most sensitive areas to climate change of the earth, owing to its unique topographic features and ecosystem. Soil pollen analysis is an important component of palaeo- ecological research, while pollen preservation and the relationship between pollen and vegetation can influence the correct interpretation of fossil pollen spectra. In this paper, 36 pollen samples, which come from four meadows and two forest soil pollen profiles, have been analyzed to determine relationships between pollen and vegetation and pollen preservation on the northeastern Qinghai-Tibetan Plateau. The relationship between pollen and vegetation shows that the surface pollen assemblages can represent regional vegetation characteristics moderately, while Betula and Populus pollen is absent in the soil surface for Betula and Populus mixed forest. Artemisia, Chenopodiaceae, Ephedra, Pinus, Hippophae etc. are over-represented pollen taxa, Leguminosae, Ranunculaceae, Rosaceae, Gramineae etc. are under-represented pollen taxa. The study of pollen preservation indicates that pollen concentrations decrease with the increase of soil depths, more pollen taxa are present in surface soils than in deep levels, and more than 75% pollen grains will be lost from the surface soils to deep levels. Pollen sorting preservation function should be noticed. Artemisia and Chenopodiaceae can be preserved well and have higher pollen percentages in deeper levels. Cyperaceae and Populus are preserved worse, Populus pollen is absent and Cyperaceae has higher pollen percentages in the surface soil than in the deep levels. The high soil pH values are the most destructive factors for pollen preservation on the northeastern Qinghai-Tibetan Plateau. Pollen concentrations decrease sharply when the soil pH values are over 7.6. Downward leaching of pollen is unimportant in this study.