Spatiotemporal characteristics of enzymatic hotspots in subtropical forests: In situ evidence from 2D zymography images
Spatiotemporal characteristics of enzymatic hotspots in subtropical forests: In situ evidence from 2D zymography images
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亚热带森林酶热点的时空特征：二维酶谱图像的原位证据
DOI：
10.1016/j.catena.2022.106365
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发表时间：
2022-05-20
期刊：
影响因子：
6.2
通讯作者：
Tian, Xingjun
中科院分区：
文献类型：
--
作者：
Cao, Tingting;Kong, Xiangshi;Tian, Xingjun
土壤酶在森林生态系统有机质分解和养分循环中起着重要作用。然而，异质土壤中原位酶活性的时空特征及其驱动因素仍然知之甚少。应用土壤酶谱法，研究了华南地区栓皮栎（Quercus variabilis）和马尾松（Pinus massoniana）纯林和混交林土壤酶活性沿沿着土壤剖面（28 cm）的季节动态。从时间上看，所有森林土壤中的酶热点区域在夏季最大（21.9% +/- 7.1%），秋季最小（6.1% +/- 4.9%），春季（13.4% +/- 5.9%）和冬季（12.5% +/- 7.7%）为中等大小。土壤温度和水分的变化是导致其季节性变化的主要原因。在空间分布上，0-10 cm（6.7% +/- 3.8%）的酶活性热点面积最大，其次是10-20 cm（5.1% +/- 3.9%）和20-28 cm（2.6% +/- 2.3%）。混交林的酶活性热点面积（6.5-33.3%）大于栎类纯林（1.3-28.5%）和松树纯林（0.2-22.8%）。混交林对酶热点区的积极影响主要归因于混交林比纯林具有更高的微生物生物量和土壤动物丰度，尤其是在干旱和寒冷的气候条件下。这些结果表明，干旱和寒冷对酶的热点区域的负面影响可以减轻混交林。这项研究提供了第一个现场证据的季节性动态的酶热点在森林土壤剖面，这是至关重要的了解养分循环和生态系统功能。
Soil enzymes play a central role in organic matter decomposition and nutrient cycling in forest ecosystems. However, the spatiotemporal characteristics of in situ enzyme activities in heterogeneous soil and their drivers are still poorly understood. We applied soil zymography in the field to visualize the seasonal dynamics of enzyme activity along soil profiles (28 cm depth) in Quercus variabilis (oak) and Pinus massoniana (pine) pure and mixed forests in southern China. Temporally, the enzymatic hotspot areas were largest in summer (21.9% +/- 7.1%), smallest in autumn (6.1% +/- 4.9%), and medium-sized in spring (13.4% +/- 5.9%) and winter (12.5% +/- 7.7%) in all forest soils. The seasonal characteristics were attributed to changes in soil temperature and moisture. Spatially, the enzymatic hotspot areas were the largest at 0-10 cm (6.7% +/- 3.8%), followed by 10-20 cm (5.1% +/- 3.9%) and 20-28 cm (2.6% +/- 2.3%) in all forest soils. In addition, the enzymatic hotspot areas of mixed forest (6.5-33.3%) were larger than those of pure oak (1.3-28.5%) and pine (0.2-22.8%) forests. This positive effect of mixed forest on enzymatic hotspot areas was mainly attributed to the higher microbial biomass and total soil faunal abundance than those in pure forests, especially under dry and cold climate conditions. These results suggest that the negative effects of drought and cold on enzymatic hotspot areas could be mitigated in the mixed forest. This study provided the first in situ evidence of the seasonal dynamics of enzymatic hotspots in forest soil profiles, which are of paramount importance for understanding nutrient cycling and ecosystem functioning.