Vertical variations in leaf functional traits of three typical ferns in mixed broadleaved- Korean pine forest

doi:10.17521/cjpe.2022.0423

Abstract

Abstract:

Aims Understanding the differences in leaf functional traits and their correlations in ferns at different vertical heights can provide a scientific basis for revealing the resource utilization strategies of large fern fronds.

Methods Individuals of three fern species in a mixed broadleaved-Korean pine (Pinus koraiensis) forest, i.e., Dryopteris crassirhizoma, Athyrium brevifrons and Matteuccia struthiopteris were divided into upper, middle, and lower layers according to the vertical height of leaves. We measured specific leaf area, leaf dry matter content, net photosynthetic rate, instantaneous water use efficiency, leaf nitrogen content and leaf phosphorus content, as well as the light environment and soil factors of each individual plant to reveal the vertical variation patterns and correlations of leaf functional traits.

Important findings (1) Leaf dry matter content of the three fern species increased with the vertical height of the fronds, but specific leaf area showed no variation. The net photosynthetic rate of A. brevifrons and M. struthiopteris showed an increasing trend with the increases of vertical height of fronds, the instantaneous water use efficiency of M. struthiopteris increased and then decreased with the vertical height of the fronds, and leaf nitrogen content gradually decreased; leaf phosphorus content of D. crassirhizoma showed an increase and then decreased trend. (2) There were positive correlations between leaf nitrogen content and specific leaf area, and also between instantaneous water use efficiency and net photosynthetic rate. There were negative correlations between leaf nitrogen content and leaf dry matter content, and between leaf dry matter content and specific leaf area. The correlations among those leaf functional traits did not differ significantly among different vertical heights. (3) Soil available phosphorus content and soil pH were the main factors affecting the variation of leaf functional traits at different vertical heights, with soil available phosphorus content having the highest explanatory degree to the variation of leaf functional traits. Our results indicated that there were vertical differences in leaf functional traits of large ferns in the mixed broadleaved-Korean pine forest, but the rate of change among individual characters was basically constant, the effects of light environment and soil factors on the variation of leaf functional traits differed among vertical heights. This study provided reference for further research on the mechanism of leaf functional traits variation in different vertical heights of ferns in understory.

Key words: leaf functional trait, fern, vertical height, correlation, environmental factor

ZHAO Meng-Juan, JIN Guang-Ze, LIU Zhi-Li. Vertical variations in leaf functional traits of three typical ferns in mixed broadleaved- Korean pine forest[J]. Chin J Plant Ecol, 2023, 47(8): 1131-1143.

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URL: https://www.plant-ecology.com/EN/10.17521/cjpe.2022.0423

https://www.plant-ecology.com/EN/Y2023/V47/I8/1131

Figures/Tables 6

Fig. 1 Three typical ferns in mixed broadleaved-Korean pine forest. L, lower layer; M, middle layer; U, upper layer. AN, available nitrogen; AP, available phosphorus; SWC, soil water content; TN, total nitrogen; TP, total phosphorus.

Table 1 Profile of environmental factors in the habitats of the three ferns (mean ± SE)

环境因子 Environmental factor	粗茎鳞毛蕨 Dryopteris crassirhizoma	东北蹄盖蕨 Athyrium brevifrons	荚果蕨 Matteuccia struthiopteris
冠层开放度 Canopy openness (%)	24.29 ± 1.04^a	24.90 ± 0.66^a	23.68 ± 2.45^a
土壤水分含量 Soil water content	0.90 ± 0.09^a	0.87 ± 0.17^a	0.99 ± 0.12^a
土壤全氮含量 Soil total nitrogen content (mg·g^-1)	9.32 ± 0.74^a	6.57 ± 0.91^b	9.06 ± 0.64^ab
土壤全磷含量 Soil total phosphorus content (mg·g^-1)	0.82 ± 0.08^a	0.89 ± 0.16^a	0.88 ± 0.10^a
土壤pH Soil pH	5.67 ± 0.11^ab	5.31 ± 0.10^b	5.76 ± 0.11^a
土壤有效氮含量 Soil available nitrogen content (mg·g^-1)	0.59 ± 0.05^a	0.50 ± 0.06^a	0.59 ± 0.03^a
土壤有效磷含量 Soil available phosphorus content (mg·g^-1)	0.02 ± 0.00^a	0.01 ± 0.00^a	0.02 ± 0.00^a

Fig. 2 Differences in leaf functional traits of three typical ferns in mixed broadleaved-Korean pine forest. A.bre, Athyrium brevifrons; D.cra, Dryopteris crassirhizoma; M.str, Matteuccia struthiopteris. LDMC, leaf dry matter content; LNC, leaf nitrogen content; LPC, leaf phosphorus content; Pn, leaf net photosynthetic rate; SLA, specific leaf area; WUEi, instantaneous water use efficiency. Different uppercase letters indicate significant differences between species (p < 0.05), and different lowercase letters indicate significant intraspecific differences (p < 0.05). The black dashed line represents the average value.

Fig. 3 Correlation of leaf functional traits at different vertical heights in three typical ferns in mixed broadleaved-Korean pine forest. Corr, correlation coefficient; L, lower layer; M, middle layer; U, upper layer. A, leaf net photosynthetic rate; LDMC, leaf dry matter content; LNC, leaf nitrogen content; LPC, leaf phosphorus content; SLA, specific leaf area; WUEi, instantaneous water use efficiency. *, p < 0.05; **, p < 0.01; ***, p < 0.001.

Fig. 4 Differences in leaf trait correlations among different heights for three typical ferns in mixed broadleaved-Korean pine forest. A, leaf net photosynthetic rate; LDMC, leaf dry matter content; LNC, leaf nitrogen content; LPC, leaf phosphorus content; SLA, specific leaf area; WUEi, instantaneous water use efficiency. The colored solid lines in the figure indicate that the correlations between traits were significant, the black solid line indicates that the three solid lines overlap.

Fig. 5 Redundancy analysis (RDA) ranking of leaf functional traits and environmental factors in three typical ferns in mixed broadleaved-Korean pine forest. A, Lower layer; B, Middle layer; C, Upper layer. A, leaf net photosynthetic rate; AN, soil available nitrogen content; AP, soil available phosphorus content; CO, canopy openness; LDMC, leaf dry matter content; LNC, leaf nitrogen content; LPC, leaf phosphorus content; pH, soil pH; SLA, specific leaf area; SWC, soil water content; TN, soil total nitrogen content; TP, soil total phosphorus content; WUEi, instantaneous water use efficiency.

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