Growth response of mycorrhizal Fraxinus mandshurica and Larix gmelinii seedlings to dry and wet deposition of atmospheric reduced nitrogen

doi:10.17521/cjpe.2024.0474

Abstract

Abstract:

Aims This study examines the growth responses of major afforestation tree species in Northeast China, specifically Fraxinus mandshurica (a broadleaf species associated with arbuscular mycorrhizal fungi) and Larix gmelinii (a coniferous species associated with ectomycorrhizal fungi), to varying levels of dry and wet deposition of reduced nitrogen. The study aims to enhance our understanding of the relationship between seedling growth patterns and atmospheric nitrogen deposition forms, thereby providing a theoretical foundation for precise nutrient management in seedling cultivation.

Methods The research utilized arbuscular mycorrhizal (AM) seedlings of F. mandshuricaand ectomycorrhizal (ECM) seedlings of L. gmelinii as test plants, and simulated varying levels of dry and wet reduced nitrogen deposition: 0 (CK), 35 (ND-35), 70 (ND-70), 35 (NW-35), and 70 (NW-70) kg N·hm^-2·a^-1. We assessed changes in seedling growth, photosynthetic capacity, root development, and mycorrhizal infection rates of the two types of seedlings.

Important findings Under conditions of atmospheric dry and wet nitrogen deposition, seedlings of both mycorrhizal types gradually reduced their mycorrhizal dependence. The primary response are the enhancement of their photosynthetic rate and an increase in root absorption capacity. (1) During nitrogen dry deposition, a significant increase in leaf and total biomass was observed for arbuscular mycorrhizal seedling of F. mandshurica, attributed to changes in photosynthetic capacity. Under the ND-70 treatment, the net photosynthetic rate, total chlorophyll content, and leaf biomass increased by 49.61%, 76.29% and 53.84% respectively, compared to the control. In contrast, during nitrogen wet deposition, nitrogen use efficiency increased primarily due to an increased contact area between absorbing roots and soil. Under NW-35 and NW-70 treatments, the surface area of absorbing roots increased by 14.96% and 16.17%, respectively, compared to the control. (2) Ectomycorrhizal seedlings of L. gmelinii exhibited a more pronounced response to nitrogen wet deposition, primarily enhanced the absorption capacity of the root system through the elongation and thinning of the absorbing roots. Under NW-70 treatment, the absorbing root length increased by 20.70% compared to the control, while the average diameter and cortical thickness of the absorbing roots decreased by 10.14% and 27.25%, respectively. The study performed an in-depth analysis of the relationship between mycorrhizal types and atmospheric reduced nitrogen deposition, serving as a reference for the precise nutrient management for tree seedlings with different mycorrhizal types.

Key words: Fraxinus mandshurica, Larix gmelinii, nitrogen deposition, seedling growth, photosynthetic capacity, absorbing root, mycorrhizal fungi

ZHANG Cheng-Hang, WEI Xing, WU Chun-Ze, WANG Yu-Yao, LI Hao-Nan. Growth response of mycorrhizal Fraxinus mandshurica and Larix gmelinii seedlings to dry and wet deposition of atmospheric reduced nitrogen[J]. Chin J Plant Ecol, 2026, 50(3): 649-659.

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URL: https://www.plant-ecology.com/EN/10.17521/cjpe.2024.0474

https://www.plant-ecology.com/EN/Y2026/V50/I3/649

Figures/Tables 8

References 47

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树种 Tree species	处理 Treatment	铵态氮含量 NH₄⁺-N content (mg^.kg^-1)	硝态氮含量 NO₃^--N content (mg^.kg^-1)	有效氮含量 AN content (mg^.kg^-1)	土壤pH Soil pH
水曲柳 Fraxinus mandshurica	CK	14.76 ± 1.22^c	45.67 ± 1.33^c	61.10 ± 1.87^c	5.67 ± 0.09^a
	ND-35	15.15 ± 1.61^c	48.84 ± 3.55^c	63.98 ± 1.96^c	5.64 ± 0.07^a
	ND-70	17.90 ± 1.04^c	50.20 ± 1.72^c	68.10 ± 2.09^c	5.57 ± 0.06^a
	NW-35	69.16 ± 2.49^b	60.63 ± 1.61^b	119.79 ± 3.38^b	5.57 ± 0.04^a
	NW-70	136.02 ± 4.38^a	71.11 ± 2.77^a	168.41 ± 3.68^a	5.48 ± 0.03^a
兴安落叶松 Larix gmelinii	CK	13.60 ± 2.18^c	46.77 ± 1.12^c	60.37 ± 2.87^c	5.66 ± 0.08^a
	ND-35	15.14 ± 2.10^c	47.74 ± 1.28^c	62.88 ± 3.37^c	5.63 ± 0.06^a
	ND-70	15.95 ± 2.61^c	49.93 ± 1.04^c	65.89 ± 2.07^c	5.57 ± 0.04^a
	NW-35	74.53 ± 2.40^b	62.28 ± 1.24^b	136.70 ± 2.09^b	5.53 ± 0.04^a
	NW-70	107.68 ± 5.07^a	77.16 ± 1.75^a	184.84 ± 4.88^a	5.51 ± 0.06^a

树种 Tree species	处理 Treatment	铵态氮含量 NH₄⁺-N content (mg^.kg^-1)	硝态氮含量 NO₃^--N content (mg^.kg^-1)	有效氮含量 AN content (mg^.kg^-1)	土壤pH Soil pH
水曲柳 Fraxinus mandshurica	CK	14.76 ± 1.22^c	45.67 ± 1.33^c	61.10 ± 1.87^c	5.67 ± 0.09^a
	ND-35	15.15 ± 1.61^c	48.84 ± 3.55^c	63.98 ± 1.96^c	5.64 ± 0.07^a
	ND-70	17.90 ± 1.04^c	50.20 ± 1.72^c	68.10 ± 2.09^c	5.57 ± 0.06^a
	NW-35	69.16 ± 2.49^b	60.63 ± 1.61^b	119.79 ± 3.38^b	5.57 ± 0.04^a
	NW-70	136.02 ± 4.38^a	71.11 ± 2.77^a	168.41 ± 3.68^a	5.48 ± 0.03^a
兴安落叶松 Larix gmelinii	CK	13.60 ± 2.18^c	46.77 ± 1.12^c	60.37 ± 2.87^c	5.66 ± 0.08^a
	ND-35	15.14 ± 2.10^c	47.74 ± 1.28^c	62.88 ± 3.37^c	5.63 ± 0.06^a
	ND-70	15.95 ± 2.61^c	49.93 ± 1.04^c	65.89 ± 2.07^c	5.57 ± 0.04^a
	NW-35	74.53 ± 2.40^b	62.28 ± 1.24^b	136.70 ± 2.09^b	5.53 ± 0.04^a
	NW-70	107.68 ± 5.07^a	77.16 ± 1.75^a	184.84 ± 4.88^a	5.51 ± 0.06^a

树种 Tree species	处理 Treatment	叶面积 Leaf area (cm²)	净光合速率 P_n(μmol·m^-2·s^-1)	气孔导度 G_s(μmol·m^-2·s^-1)	蒸腾速率 T_r(μmol·m^-2·s^-1)	胞间CO₂浓度 C_i(μmol·m^-2·s^-1)
水曲柳 Fraxinus mandshurica	CK	87.05 ± 6.47^b	2.62 ± 0.26^b	0.03 ± 0.01^b	1.01 ± 0.06^c	233.20 ± 9.76^b
	ND-35	108.68 ± 5.71^ab	3.76 ± 0.22^a	0.04 ± 0.01^a	1.31 ± 0.09^ab	243.40 ± 8.82^ab
	ND-70	133.92 ± 13.01^a	3.92 ± 0.26^a	0.04 ± 0.01^a	1.52 ± 0.09^a	265.20 ± 10.24^a
	NW-35	90.29 ± 5.61^b	2.96 ± 0.12^b	0.03 ± 0.01^b	0.93 ± 0.05^c	247.40 ± 9.44^ab
	NW-70	107.02 ± 12.93^ab	3.10 ± 0.15^b	0.03 ± 0.01^b	1.11 ± 0.07^bc	265.60 ± 5.31^a
兴安落叶松 Larix gmelinii	CK	13.74 ± 1.62^a	2.07 ± 0.14^a	0.03 ± 0.01^a	0.67 ± 0.04^a	261.80 ± 15.22^b
	ND-35	14.53 ± 0.55^a	2.29 ± 0.12^a	0.03 ± 0.01^a	0.69 ± 0.03^a	257.00 ± 10.77^b
	ND-70	16.08 ± 2.30^a	2.39 ± 0.16^a	0.03 ± 0.01^a	0.72 ± 0.03^a	280.80 ± 13.26^ab
	NW-35	15.91 ± 1.40^a	2.25 ± 0.19^a	0.03 ± 0.01^a	0.71 ± 0.04^a	270.60 ± 10.62^b
	NW-70	17.07 ± 1.46^a	2.44 ± 0.13^a	0.03 ± 0.01^a	0.72 ± 0.02^a	309.40 ± 10.66^a

树种 Tree species	处理 Treatment	叶面积 Leaf area (cm²)	净光合速率 P_n(μmol·m^-2·s^-1)	气孔导度 G_s(μmol·m^-2·s^-1)	蒸腾速率 T_r(μmol·m^-2·s^-1)	胞间CO₂浓度 C_i(μmol·m^-2·s^-1)
水曲柳 Fraxinus mandshurica	CK	87.05 ± 6.47^b	2.62 ± 0.26^b	0.03 ± 0.01^b	1.01 ± 0.06^c	233.20 ± 9.76^b
	ND-35	108.68 ± 5.71^ab	3.76 ± 0.22^a	0.04 ± 0.01^a	1.31 ± 0.09^ab	243.40 ± 8.82^ab
	ND-70	133.92 ± 13.01^a	3.92 ± 0.26^a	0.04 ± 0.01^a	1.52 ± 0.09^a	265.20 ± 10.24^a
	NW-35	90.29 ± 5.61^b	2.96 ± 0.12^b	0.03 ± 0.01^b	0.93 ± 0.05^c	247.40 ± 9.44^ab
	NW-70	107.02 ± 12.93^ab	3.10 ± 0.15^b	0.03 ± 0.01^b	1.11 ± 0.07^bc	265.60 ± 5.31^a
兴安落叶松 Larix gmelinii	CK	13.74 ± 1.62^a	2.07 ± 0.14^a	0.03 ± 0.01^a	0.67 ± 0.04^a	261.80 ± 15.22^b
	ND-35	14.53 ± 0.55^a	2.29 ± 0.12^a	0.03 ± 0.01^a	0.69 ± 0.03^a	257.00 ± 10.77^b
	ND-70	16.08 ± 2.30^a	2.39 ± 0.16^a	0.03 ± 0.01^a	0.72 ± 0.03^a	280.80 ± 13.26^ab
	NW-35	15.91 ± 1.40^a	2.25 ± 0.19^a	0.03 ± 0.01^a	0.71 ± 0.04^a	270.60 ± 10.62^b
	NW-70	17.07 ± 1.46^a	2.44 ± 0.13^a	0.03 ± 0.01^a	0.72 ± 0.02^a	309.40 ± 10.66^a

树种 Tree species	处理 Treatment	根尖数 Root tips	根长度 Root length (cm)	根表面积 Root surface area (cm²)	根体积 Root volume (cm³)	根平均直径 Root average diameter (μm)
水曲柳 Fraxinus mandshurica	CK	3608.33 ± 212.69^b	1394.02 ± 34.07^ab	133.27 ± 3.96^c	1.08 ± 0.02^a	985.16 ± 12.52^c
	ND-35	4068.67 ± 105.66^ab	1372.66 ± 35.26^b	137.71 ± 2.13^c	1.13 ± 0.03^a	1020.39 ± 18.39^bc
	ND-70	4200.00 ± 186.58^ab	1515.32 ± 54.77^ab	140.27 ± 2.99^bc	1.12 ± 0.02^a	1041.25 ± 13.46^b
	NW-35	4278.00 ± 291.16^ab	1480.63 ± 46.04^ab	153.21 ± 6.21^ab	1.12 ± 0.02^a	1034.18 ± 34.13^bc
	NW-70	4577.00 ± 264.68^a	1548.23 ± 68.31^a	154.83 ± 4.88^a	1.14 ± 0.02^a	1123.01 ± 12.92^a
兴安落叶松 Larix gmelinii	CK	539.33 ± 21.30^a	112.50 ± 3.99^b	11.64 ± 0.29^a	0.11 ± 0.01^b	978.77 ± 25.63^a
	ND-35	535.33 ± 18.62^a	121.67 ± 6.60^ab	11.71 ± 0.13^a	0.12 ± 0.01^ab	976.02 ± 35.47^ab
	ND-70	547.67 ± 12.14^a	125.97 ± 7.78^ab	11.68 ± 0.11^a	0.12 ± 0.01^ab	923.84 ± 19.36^ab
	NW-35	587.67 ± 34.38^a	127.48 ± 8.17^ab	12.20 ± 0.10^a	0.12 ± 0.01^ab	919.01 ± 16.56^ab
	NW-70	583.67 ± 25.56^a	135.79 ± 3.91^a	11.84 ± 0.18^a	0.13 ± 0.01^a	879.49 ± 34.22^b