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Advantages of Small-Seeded Species in Forests : Win-Win for Temporal and Spatial Dispersal among Seeds in Rhododendron

Wang Haiyang, Lai Xiaohong, Zhang Yanru, Chen Hong

Polish Journal of Ecology

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2019

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Vol. 67, nr 1

17--32

EN

There is little consistent evidence for evolutionary associations from seed production to seedling fitness. In this study, 20 species of Rhododendron genus were selected from subtropical forests of southwest China; the life-history functional traits such as the seed size, seed number per twig, germination traits, dispersal and seedling survival were investigated, the ecological relationships among them were tested and the advantages of small-seeded species were discussed. The results show that the quantitative parameters of germination, such as the germination rate, potential, and index are positively correlated with seed number produced per stem, while temporal parameters, such as germination peak timing and duration are positively correlated with seed size. The two results indicate that different Rhododendron species with different seed sizes and relative seed number can deal with varying environments according to spatial dispersal or time dispersal, respectively, and the advantages of smaller seeds in the aspect of sprouting vigour, dispersal ability and seedling survival may lay the foundation for the establishment of small-seeded plants in the forest.

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Relationship between seed size and plant abundance in an alpine meadow of the Qinghai-Tibetan Plateau

Liu B., Luo Y.

Polish Journal of Ecology

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2009

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Vol. 57, nr 3

573-579

EN

Theoretical and field studies on seed size and plant abundance relationship have been conducted in various communities. However, inconsistent patterns have emerged from these studies, and still little is known about alpine meadows. Here we identified four models and their predictions: the seed size/number trade-off model (SSNTM), the succession model (SM), the spatial competition model (SCM), and the triangle model (TM), in order to assess the relationship between seed size and abundance in alpine meadows, and to elucidate underlying mechanisms. The study site was situated on the eastern Qinghai-Tibetan Plateau at 3500 m above sea level. From 1999 through 2001, two indices of plant abundance (aboveground biomass and density) were simultaneously measured in 45 quadrates (0.25 m[^2]). Data for 101 plant species (mostly Cyperaceae, Poaceae, Asteraceae, Ranunculaceae and forbs) showed that seed size is like log normal distributed, and it slightly skewed in smaller-sized seeds. The SSNTM, the TM, the SM and the SCM models were not supported in this alpine meadow, and the relationship between seed size and abundance was always positive (although in some samples, the relationship was not significant). The positive correlation between seed size and abundance observed for some grassland communities was also demonstrated in the alpine meadow. It suggests that seed size depends on the plant growth form, but the biomass-density relationship is inconsistent with previous studies. This suggests that the measure of abundance used in these studies is not the only reason for inconsistency of seed size.

3

Wpływ wielkości nasion na niezbędną długość przewodu pneumatycznego w procesie ekspandowania nasion

Konopko H.

Inżynieria Rolnicza

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2006

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R. 10, nr 5(80)

291-296

PL

Celem pracy było określenie wpływu wielkości nasion na przebieg i rezultaty procesu ekspandowania nasion w strumieniu gorącego powietrza w pionowym przewodzie pneumatycznym. Analizy problemu dokonano na podstawie wyników symulacji komputerowej procesu dla dwóch klas ziarnowych tego samego gatunku nasion. Wykazały one, że dla każdej klasy ziarnowej należy odrębnie ustalać optymalne, z punktu widzenia jakości produktu, parametry procesu.

EN

The purpose of the study was to determine the impact of seed size on the course and results of the seed expansion process in a stream of hot air in a vertical pneumatic tube. The problem analysis was done based on the results of a computer simulation of the process for two grain classes of the same grain type. It was found that for each grain class it is necessary to establish separately the process parameters that would be optimal from the point of view of the quality of the product.