Intraspecific variation of defensive traits of Lithocarpus dealbatus and the effect on the distributional boundary of a tree species

In order to study the effect on the formation of distribution of Lithocarpus dealbatus,intraspecific variation and covariation of thickness,hardness,total phenols content (TPC) and condensed tannin (CT) in leaves from 8 populations across the distribution area from north to south were quantified.The results showed that the variation of four defensive traits were 19.31%,43.72%,20.82% and 32.56%,respectively.The total intraspecific variation was contributed by the difference among populations and individuals.The values of chemical defense in leaves increased with rising elevation.The leaves from Lithocarpus dealbatus populations showed the trade-off tragedy between growth and defense.The populations from northern edge of distribution area had the heaviest integrated defensive investment which meant low growth and high defense,and formed the most northward edge of the distribution area.The populations from southern edge of distribution showed low defense and rapid growth,which formed the most southward distribution range.It is conclude that intraspecific variation of defensive traits of the leaves has effect on the distribution of Lithocarpus dealbatus along the latitude direction.