Browsing by Author "Lin, Shuyan"

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    A geometrical model for testing bilateral symmetry of bamboo leaf with a simplified Gielis equation
    (Wiley Open Access, 2016) Lin, Shuyan; Zhang, Li; Reddy, Gadi V. P.; Hui, Cang; Gielis, Johan; Ding, Yulong; Shi, Peijian
    The size and shape of plant leaves change with growth, and an accurate description of leaf shape is crucial for describing plant morphogenesis and development. Bilateral symmetry, which has been widely observed but poorly examined, occurs in both dicot and monocot leaves, including all nominated bamboo species (approximately 1,300 species), of which at least 500 are found in China. Although there are apparent differences in leaf size among bamboo species due to genetic and environmental profiles, bamboo leaves have bilateral symmetry with parallel venation and appear similar across species. Here, we investigate whether the shape of bamboo leaves can be accurately described by a simplified Gielis equation, which consists of only two parameters (leaf length and shape) and produces a perfect bilateral shape. To test the applicability of this equation and the occurrence of bilateral symmetry, we first measured the leaf length of 42 bamboo species, examining >500 leaves per species. We then scanned 30 leaves per species that had approximately the same length as the median leaf length for that species. The leaf-shape data from scanned profiles were fitted to the simplified Gielis equation. Results confirmed that the equation fits the leaf-shape data extremely well, with the coefficients of determination being 0.995 on average. We further demonstrated the bilateral symmetry of bamboo leaves, with a clearly defined leaf-shape parameter of all 42 bamboo species investigated ranging from 0.02 to 0.1. This results in a simple and reliable tool for precise determination of bamboo species, with applications in forestry, ecology, and taxonomy.
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    Influence of the physical dimension of leaf size measures on the goodness of fit for Taylor's power law using 101 bamboo taxa
    (Elsevier, 2019) Shi, Peijian; Zhao, Lei; Ratkowsky, David A.; Niklas, Karl J.; Huang, Weiwei; Lin, Shuyan; Ding, Yulong; Hui, Cang; Li, Bai-Lian
    ENGLISH ABSTRACT: The mean and variance of ecological measures usually follow a power-law relationship, referred to as Taylor's power law (TPL). Leaves are important organs for photosynthesis, and leaf size is closely related to photosynthetic potential. Leaf size has different physical measures, such as leaf length, area, and fresh or dry weight. However, it has not been reported whether these leaf size measures follow TPL and whether the estimates of the TPL exponent reflect basic topological constraints. Considering that the variation of leaf size can affect the photosynthetic capacity of leaves and plant competitive abilities in communities, we examined the effects of different physical dimensions of leaf size (including leaf length, area, and fresh and dry weight) on the estimate of the scaling exponent and the goodness of fit of TPL for 101 bamboo species, varieties, forms, and cultivars, using 90-100 leaves for each type of plant. All leaf size measures follow TPL. However, the goodness of fit increases with the physical dimension of the leaf size measure (e.g., from 1D leaf length to 3D leaf weight). Interestingly, no significant differences in the estimates of the TPL exponent were detected among any of the physical dimensions (1D to 3D) because the 95% confidence intervals of the differences between any two groups of bootstrap replicates of the exponents of TPL obtained from different leaf size measures did not include 0. In other words, the TPL exponents of leaf size measures from the different physical dimensions could be deemed identical. We found that leaf dry weight provides the best fit of TPL and the most reliable estimate of the exponent among the four leaf size measures used in this study, perhaps because it is the best representative of the energy allocated to individual leaves.
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    Leaf shape influences the scaling of leaf dry mass vs. area : a test case using bamboos
    (Springer, 2020-01-21) Lin, Shuyan; Niklas, Karl J.; Wan, Yawen; Holscher, Dirk; Hui, Cang; Ding, Yulong; Shi, Peijian
    Key message A highly significant and positive scaling relationship between bamboo leaf dry mass and leaf surface area was observed; leaf shape (here, represented by the quotient of leaf width and length) had a significant influence on the scaling exponent of leaf dry mass vs. area. Context The scaling of leaf dry mass vs. leaf area is important for understanding how plants effectively intercept sunlight and invest carbon to do so. However, comparatively few, if any, studies have focused on whether leaf shape influences this scaling relationship. Aims In order to explore the effects of leaf shape on the scaling relationship between leaf dry mass and area, we examined 101 species, varieties, forms, and cultivars of bamboo growing in China and identified the relationship between the scaling exponent of leaf dry mass vs. area and leaf shape. This taxon was used because its leaf shape is conserved across species and, therefore, easily quantified. Methods Ten thousand and forty-five leaves from 101 bamboo species, varieties, forms, and cultivars growing in China were collected, and leaf dry mass, the quotient of leaf width and length, leaf area, and leaf dry mass per unit area were measured. The effect of leaf shape that can be easily quantified using the quotient of leaf width and length on the relevant and ecologically important scaling exponents was explored using this data base. Results Leaf dry mass and area differed significantly across bamboo genera, and even within the same genus. However, a statistically robust log-log linear and positive scaling relationship was observed for mass and area with a 1.115 scaling exponent (95% CI = 1.107, 1.122; r(2) = 0.907). Leaf shape had a significant influence on the numerical values of the scaling exponent of leaf dry mass vs. area. When the median of the quotient of leaf width and length was below 0.125, the numerical value of the scaling exponent increased with increasing quotient of leaf width and length. When the median of the quotient of leaf width and length was above 0.125, the scaling exponent numerically decreased toward 1.0. Conclusion We show, for the first time, that a significant relationship exists between leaf shape and the numerical values of scaling exponents governing the scaling of leaf dry mass with respect to leaf area. In addition, we show that with the quotient of leaf width and length increasing mean LMA increases, which implies a negative correlation between mean LMA and the estimated exponent of leaf dry mass vs. area for the grouped data based on the sorted quotients of leaf width and length.
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    Why does not the leaf weight-area allometry of bamboos follow the 3/2-power law?
    (Frontiers Media, 2018) Lin, Shuyan; Shao, Lijuan; Hui, Cang; Song, Yu; Reddy, Gadi V. P.; Gielis, Johan; Li, Fang; Ding, Yulong; Wei, Qiang; Shi, Peijian
    The principle of similarity (Thompson, 1917) states that the weight of an organism follows the 3/2-power law of its surface area and is proportional to its volume on the condition that the density is constant. However, the allometric relationship between leaf weight and leaf area has been reported to greatly deviate from the 3/2-power law, with the irregularity of leaf density largely ignored for explaining this deviation. Here, we choose 11 bamboo species to explore the allometric relationships among leaf area (A), density (ρ), length (L), thickness (T), and weight (W). Because the edge of a bamboo leaf follows a simplified two-parameter Gielis equation, we could show that A ∝ L2 and that A ∝ T2. This then allowed us to derive the density-thickness allometry ρ ∝ Tb and the weight-area allometry W ∝ A(b+3)/2 ≈ A9/8, where b approximates −3/4. Leaf density is strikingly negatively associated with leaf thickness, and it is this inverse relationship that results in the weight-area allometry to deviate from the 3/2-power law. In conclusion, although plants are prone to invest less dry mass and thus produce thinner leaves when the leaf area is sufficient for photosynthesis, such leaf thinning needs to be accompanied with elevated density to ensure structural stability. The findings provide the insights on the evolutionary clue about the biomass investment and output of photosynthetic organs of plants. Because of the importance of leaves, plants could have enhanced the ratio of dry material per unit area of leaf in order to increase the efficiency of photosynthesis, relative the other parts of plants. Although the conclusion is drawn only based on 11 bamboo species, it should also be applicable to the other plants, especially considering previous works on the exponent of the weight-area relationship being less than 3/2 in plants.