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Pak. J. Bot., 46(4): 1261-1268, 2014.

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SEEDLING PERFORMANCE WITHIN EIGHT DIFFERENT SEED-SIZE ALPINE FORBS UNDER EXPERIMENTATION WITH IRRADIANCE AND NUTRIENT GRADIENTS

WANG DONG^1,2, ZHU YUAN-JUN^1,2, WU GAO-LİN^1,2*, AND FENG JIN³

Abstract: Relative performance of seedlings of species with different seed sizes may vary in response to resource availability, and may affect seedling growth. The objective was to test this hypothesis from alpine forbs species in the Qinghai-Tibetan Plateau. We examined the relative growth rate, allocation and performances of eight native forbs species covering a wide range of seed size in response to four light and three nutrient regimes. Light availability had a significant effect on seedling emergence time, but not on other seedling morphological performances. Seedling emergence time and seed size were negatively correlated with each other for three species within Asteraceae family, i.e. heaviest seeds emerged earlier. Seed size, nutrient availability and their interaction affected most of studied morphological and growth traits of seedlings. Fertilisation modified the relationship between seed size and seedling biomass. Our study showed that seed size and nutrient availability had significant effects on seedling performance in alpine meadows. Seedlings from the larger-seed species presented stronger advantage in initial seedling mass and height under most of resources conditions.

¹State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling 712100 Shaanxi, P.R. China

²Institute of Soil and Water Conservation of Chinese Academy of Sciences & Ministry of Water Resources, Yangling 712100 Shaanxi, P.R. China

³General Grassland Station of Gansu Province, Lanzhou 730010 Gansu, P.R. China;

* Corresponding author: e-mail: gaolinwu@gmail.com  Ph: 86-29-87012884; Fax: 86-29-87016082