Relative growth rate in relation to physiological and morphological traits for northern hardwood tree seedlings: species, light environment and ontogenetic considerations

Abstract:We performed a pot experiment in which 540 seedlings of nine non-pioneer light-demanding tree species were grown for 12 months in shade houses at three light levels, 46% daylight, 13% daylight and 2% daylight, to examine the mechanisms contributing to the coexistence of seedlings of non-pioneer light-demanding tree species in secondary successional tropical rain forest in Hainan, China. Growth and survival of tree seedlings were compared at different light levels, and the morphological and physiological correlates of high-light seedling growth and low-light survival across species were determined. For all species, mortality was very low in the 46% daylight and 13% daylight treatment but increased significantly in the 2% daylight treatment. Seedling survival in 2% daylight treatment was positively related to seed mass. Trade-off between high-light growth and low-light survival was more evident in the relationship with 2% daylight treatment as compared with 13% daylight treatment. Relative growth rate in the 2% daylight treatment was not significantly related to relative growth rate in the 13% daylight or 46% daylight treatment; although a slight negative correlation was apparent. Interspecific variation in RGRm was only closely correlated with net assimilation rate (NAR). The results provide some support for the niche-partitioning hypothesis.

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Correlations Between Biomass Allocation, Relative Growth Rate and Light Environment in Tropical Forest Saplings

Functional Ecology ◽

10.2307/2389630 ◽

1991 ◽

Vol 5 (4) ◽

pp. 485 ◽

Cited By ~ 86

Author(s):

D. A. King

Keyword(s):

Growth Rate ◽

Tropical Forest ◽

Relative Growth Rate ◽

Biomass Allocation ◽

Light Environment ◽

Relative Growth

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Effects of light availability on leaf attributes and seedling growth of four tree species in tropical dry forest

Ecological Processes ◽

10.1186/s13717-019-0206-4 ◽

2020 ◽

Vol 9 (1) ◽

Cited By ~ 1

Author(s):

Sachchidanand Tripathi ◽

Rahul Bhadouria ◽

Pratap Srivastava ◽

Rajkumari S. Devi ◽

Ravikant Chaturvedi ◽

...

Keyword(s):

Growth Rate ◽

Relative Growth Rate ◽

Tree Species ◽

Light Availability ◽

Matter Content ◽

Tree Seedlings ◽

Dry Matter Content ◽

Light Conditions ◽

Relative Growth ◽

Mean Values

Abstract Background In tropical dry forests, variation in understory light availability due to season and canopy tree density could be a governing factor in establishment and growth of tree seedlings. Species with varying life history traits are expected to respond differentially to such heterogeneity. We investigated the response of seedlings of four tree species in a tropical day forest in relation to spatiotemporal variability of light. We attempt to explore the role of leaf attributes in explaining intra- and inter-specific variations in relative growth rate. Four study sites, each with three contrasting canopy conditions, were selected along a soil moisture gradient. Seedlings of four tree species (viz., Acacia catechu, Bridelia retusa, Lagerstroemia parviflora, and Shorea robusta), varying in life history traits, were monitored for seasonal variations in growth traits across canopy condition and sites for 2 years. Results We observed a larger variation in leaf attributes for pioneer species. A. catechu showed highest mean values for leaf dry matter content, leaf nitrogen concentration, leaf phosphorus concentration, net stomatal conductance, net photosynthetic rate, and relative growth rate in high light conditions. S. robusta and B. retusa demonstrated highest mean values for all the leaf attributes (except leaf dry matter content) in low light conditions. However, intermediate values for leaf attributes were observed in L. parviflora which preferred moderate light conditions. Conclusions Seasonal variations in light availability at the forest floor appear to play an important role in the establishment and growth of tree seedlings in seasonal dry forests. Leaf attributes can be used to explain intra- and inter-specific variation in response to light availability. Leaf attributes in combinations can be used to predict relative growth rate of tree species in tropical dry environment, which apart from soil moisture is also determined by light availability due to seasonal changes and canopy tree density.

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