STUDY OF LEAF FUNCTIONAL TRAITS IN QUERCUS SEMICARPIFOLIA AND QUERCUS LANATA AT ALTITUDINAL GRADIENT IN SHIVAPURI NAGARJUNA NATIONAL PARK, KATHMANDU, NEPAL

Abstract

The present study shows the leaf traits variation of Q. semecarpifolia and Q. lanata along the altitudinal gradients and different growing life stages at Shivapuri Nagarjuna National Park. Generalized linear regression model analysis with using the value of R2 (Coefficient of determination), analyses of variance (ANOVA), mean ± standard deviation was applied for the inter-comparison of the parameters that is, specific leaf area, leaf carbon content , leaf nitrogen content, leaf phosphorus content for testing the differences among the different altitudes, between the species and among various life stages by using SPSS version 25.0 software packages. The statistical analysis shows that there is significance difference in specific leaf area, leaf nitrogen content and leaf phosphorous content along with the altitudes (p < 0.05). The result of the study showed leaf carbon content doesn’t significantly alters with altitudes (0.897>0.05) and also between the species (0.424>0.05). Similarly leaf Phosphorous content doesn’t significantly alters among the life stage (0.659>0.05). A stepwise multiple regression analysis shows a moderate effect of Specific leaf area on carbon ( R² = 0.5013), less effect on nitrogen ( R² =0.4277) and strong effects on phosphorus ( R² =0.6708). Leaf nitrogen and leaf phosphorus was positively correlated with leaf each other and negatively correlated with specific leaf area as the value was less than (P < 0.05). Specific leaf area shows no effect on the relationship between carbon, nitrogen, phosphorus and leaf Similarly for stomatal density, the significance value was found to be 0.000 (p< 0.05) so there was significance difference in the stomatal density between Quercus semicarpifolia and Quercus lanata . The density of stomata was found higher in all the plant leaves of Q. lanata than Q. semecarpifolia irrespective with altitude.