关键词: 樟子松, 人工固沙林, 衰退, 衰退原因

Abstract: The fruits and seeds of endangered plant Camellia nitidissima were collected from five natural populations in Nazishan (NZSH1, NZSH2, and NZSH3), Dawangjiang (DWJ) and Gengmaoshan (GMSH), and one artificial population in Guangxi Institute of Botany (GIXB). Based on the 15 characters of fruits and seeds, the morphological differentiation of the six populations was studied. According to the size of fruits and seeds, the six populations were in the order of GIXB > NZSH2 > DWJ > GMSH > NZSH3 > NZHS1, and there existed differences among and within the populations of C. nitidissima. The average variation coefficient of different characters among populations ranged from 0.429 (seed mass per fruit, SMPF) to 0.069 (shape of fruit, FT/FD), and the FT/FD was a relatively stable character; while the average variation coefficient of different populations ranged from 0.287 (NZSH3) to 0.155 (GXIB). In the 15 characters, the variations of 3 characters (such as fruit diameter and mass) were significant (P<0.05), and those of 7 characters (such as seed length and width) were very significant (P<0.01). There was an evident morphological differentiation among most populations. Cluster analysis showed that the morphological differentiation was not correlated with the geographic distance among populations. The major factors affecting the morphological differentiation of fruits and feeds were altitude, soil organic matter, soil water, and light transmittance of canopy.

Key words: Pinus sylvestris var.mongolica, Sand-fixation plantation forest, Decline, Decline cause