Response of soil enzyme activities to litter input changes in two secondary Castanopsis carlessii forests in subtropical China

doi:10.17521/cjpe.2017.0247

Abstract

Abstract:

Aims Enzymes play an important role in the decomposition of soil organic matter. Changes in net primary productivity in response to climate change are likely to affect litter inputs to forest soil. However, the effects of altered litter input on soil enzyme activities remain poorly understood in subtropical forests. Thus, this study is designed to find out if litter manipulation has an effect on enzymes in different subtropical Castanopsis carlessii forest.

Methods Three treatments including double litter (DL), no litter (NL) and control (CT) were installed in a secondary C. carlesii forest and a human-assisted naturally regenerated C. carlesii forest, to investigate the responses of 6 soil extracellular enzyme activities.

Important findings The activities of Cellobiohydrolase (CBH), β-1,4-N-acetylglucosaminidase (NAG), Polyphenol oxidase (PhOx) and Peroxidase (PerOx) in the secondary C. carlesii forest were higher than those in the human-assisted naturally regenerated C. carlesii forest, while acid phosphatase (AP) and β-1,4-glucosidase (βG) activities had no significant difference between the two forests. Compared to control, both NL and DL treatments decreased the activities of AP, βG and NAG, but had no effect on the activities of CBH and PerOx, and DL treatment decreased only the activity of PhOx in two forests. Except for NAG activity, the activities of AP, βG and PerOx decreased more in the human-assisted naturally regenerated C. carlesii forest than in the secondary C. carlesii forest after litter manipulaition. Both Pearson correlation analysis and redundancy analysis showed that soil enzyme activities were significantly correlated with soil moisture content, carbon (C), nitrogen (N), microbial biomass carbon (MBC) and nitrogen (MBN) contents. Therefore, changes in litter input (both increase and decrease) could decrease some major soil enzyme activities such as AP, βG and NAG in both secondary and human-assisted naturally regenerated C. carlesii forests by decreasing soil moisture content, C and N, MBC and MBN contents. Based on the responses of soil enzyme activity, we conclude that the C and N cycling in secondary C. carlesii forest could be faster compared to that in the human-assisted forest of the same species in the subtropical forest ecosystems.

http://jtp.cnki.net/bilingual/detail/html/ZWSB201806009

Key words: double litter, no litter, soil enzyme activities, secondary Castanopsis carlesii forest, human-assisted naturally regenerated Castanopsis carlesii forest

WEI Cui-Cui, LIU Xiao-Fei, LIN Cheng-Fang, LI Xian-Feng, LI Yan, ZHENG Yu-Xiong. Response of soil enzyme activities to litter input changes in two secondary Castanopsis carlessii forests in subtropical China[J]. Chin J Plant Ecol, 2018, 42(6): 692-702.

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URL: https://www.plant-ecology.com/EN/10.17521/cjpe.2017.0247

https://www.plant-ecology.com/EN/Y2018/V42/I6/692

Figures/Tables 6

References 46

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项目 Item	米槠次生林 Secondary Castanopsis carlesii forest	米槠人促更新次生林 Human-assisted naturally regenerated Castanopsis carlesii forest
平均树高 Average tree height (m)	10.80	13.70
平均胸径 Average breast diameter (cm)	12.20	16.80
林分密度 Stand density (株?hm^-2)	3788	2158
年凋落物量 Annual litter fall (g?m^-2)	698	658
细根生物量 Fine root biomass (kg?m^-3)	0.93	0.70
全C含量 Total carbon content (g?kg^-1)	20.98	16.68
全N含量 Total nitrogen content (g?kg^-1)	1.42	1.14
土壤容重 Soil bulk density (g?cm^-3)	0.95	1.10

项目 Item	米槠次生林 Secondary Castanopsis carlesii forest	米槠人促更新次生林 Human-assisted naturally regenerated Castanopsis carlesii forest
平均树高 Average tree height (m)	10.80	13.70
平均胸径 Average breast diameter (cm)	12.20	16.80
林分密度 Stand density (株?hm^-2)	3788	2158
年凋落物量 Annual litter fall (g?m^-2)	698	658
细根生物量 Fine root biomass (kg?m^-3)	0.93	0.70
全C含量 Total carbon content (g?kg^-1)	20.98	16.68
全N含量 Total nitrogen content (g?kg^-1)	1.42	1.14
土壤容重 Soil bulk density (g?cm^-3)	0.95	1.10

酶 Enzyme	缩写 Abbreviation	编号 Code	底物 Substrate	类型 Type
酸性磷酸酶 Acid phosphatase	AP	3.1.3.2	4-甲基伞形酮磷酸酯 4-MUB-phosphate	P获得水解酶 P-targeting hydrolytic
β-葡萄糖苷酶 β-1,4-glucosidase	βG	3.2.1.21	4-甲基伞形酮-β-D-葡萄糖苷 4-MUB-β-D-glucoside	C获得水解酶 C-targeting hydrolytic
纤维素水解酶 Cellobiohydrolase	CBH	3.2.1.91	4-甲基伞形酮-β-D-纤维素二糖苷 4-MUB-β-D-cellobioside	C获得水解酶 C-targeting hydrolytic
β-N-乙酰氨基葡萄糖苷酶 β-1,4-N-acetylglucosaminidase	NAG	3.1.6.1	4-甲基伞形酮-2-乙酰氨基-2-脱氧-β-D-吡喃葡萄糖苷 4-MUB-N-acetyl-β-D-lucosaminide	N获得水解酶 N-targeting hydrolytic
酚氧化酶 Phenol oxidase	PhOx	1.10.3.2	L-二羟基苯 L-DOPA	C获得氧化酶 C-targeting oxidase
过氧化物酶 Peroxidase	PerOx	1.11.1.7	L-二羟基苯 L-DOPA	C获得氧化酶 C-targeting oxidase

酶 Enzyme	缩写 Abbreviation	编号 Code	底物 Substrate	类型 Type
酸性磷酸酶 Acid phosphatase	AP	3.1.3.2	4-甲基伞形酮磷酸酯 4-MUB-phosphate	P获得水解酶 P-targeting hydrolytic
β-葡萄糖苷酶 β-1,4-glucosidase	βG	3.2.1.21	4-甲基伞形酮-β-D-葡萄糖苷 4-MUB-β-D-glucoside	C获得水解酶 C-targeting hydrolytic
纤维素水解酶 Cellobiohydrolase	CBH	3.2.1.91	4-甲基伞形酮-β-D-纤维素二糖苷 4-MUB-β-D-cellobioside	C获得水解酶 C-targeting hydrolytic
β-N-乙酰氨基葡萄糖苷酶 β-1,4-N-acetylglucosaminidase	NAG	3.1.6.1	4-甲基伞形酮-2-乙酰氨基-2-脱氧-β-D-吡喃葡萄糖苷 4-MUB-N-acetyl-β-D-lucosaminide	N获得水解酶 N-targeting hydrolytic
酚氧化酶 Phenol oxidase	PhOx	1.10.3.2	L-二羟基苯 L-DOPA	C获得氧化酶 C-targeting oxidase
过氧化物酶 Peroxidase	PerOx	1.11.1.7	L-二羟基苯 L-DOPA	C获得氧化酶 C-targeting oxidase

项目 Item	米槠次生林 Secondary Castanopsis carlesii forest			米槠人促更新次生林 Human-assisted naturally regenerated Castanopsis carlesii forest
项目 Item	对照 Control	凋落物去除 No litter	凋落物添加 Double litter	对照 Control	凋落物去除 No litter	凋落物添加 Double litter
含水量 Moisture content (%)	0.30 ± 0.00^aA	0.23 ± 0.01^bA	0.29 ± 0.03^abA	0.26 ± 0.06^aA	0.21 ± 0.01^aA	0.25 ± 0.03^aA
pH值 pH value	5.11 ± 0.14^aA	5.10 ± 0.04^aA	4.91 ± 0.16^aA	5.25 ± 0.17^aA	5.11 ± 0.02^aA	5.13 ± 0.10^aA
全碳 Total carbon (g·kg^-1)	20.98 ± 2.75^aA	12.41 ± 1.75^bA	16.49 ± 0.47^bB	16.68 ± 0.44^aB	12.77 ± 0.09^bA	14.71 ± 3.00^abA
全氮 Total nitrogen (g·kg^-1)	1.42 ± 0.09^aA	0.93 ± 0.12^cA	1.14 ± 0.02^bB	1.14 ± 0.09^aB	0.88 ± 0.07^bA	1.02 ± 0.19^abA
可溶性有机碳 Dissolved organic carbon (mg·kg^-1)	49.15 ± 8.37^aA	29.77 ± 9.46^bA	55.58 ± 8.7^aA	48.86 ± 6.76^aA	47.11 ± 10.09^aA	49.52 ± 6.46^aA
可溶性有机氮 Dissolved organic nitrogen (mg·kg^-1)	2.08 ± 0.02^aA	1.85 ± 0.09^aA	0.74 ± 0.15^bB	2.26 ± 0.36^aA	2.18 ± 0.43^aA	1.86 ± 0.44^aA
NH₄⁺ (mg·kg^-1)	37.49 ± 0.69^bA	26.5 ± 3.21^cA	52.6 ± 0.6^aA	26.99 ± 4.01^bB	22.04 ± 3.12^aA	29.63 ± 4.41^aB
矿质氮 Mineral nitrogen (mg·kg^-1)	38.08 ± 0.52^bA	27.22 ± 3.31^cA	53.05 ± 0.82^aA	27.96 ± 3.94^aB	22.37 ± 3.24^bA	30.98 ± 4.41^aB
微生物生物量碳 Microbial biomass carbon (mg·kg^-1)	315 ± 33^abA	225 ± 66^bA	371 ± 57^aA	258 ± 17^aB	171 ± 5^cA	221 ± 23^bB
微生物生物量氮 Microbial biomass nitrogen (mg·kg^-1)	29.33 ± 6.30^aA	13.41 ± 2.27^bA	26.38 ± 5.36^aA	36.56 ± 3.49^aA	14.61 ± 2.58^cA	23.05 ± 5.07^bA