題目：Influences of plant traits on the retention and redistribution of bioavailable nitrogen within the plant-soil system

期刊：

作者：Junsheng Huang, Meifeng Deng, Zhou Jia, Sen Yang, Lu Yang, Shengnan Pan, Pengfei Chang, Chao Liu, Lingli Liu

通訊作者：Lingli Liu

地址：State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Xiangshan, Beijing 100093, China

Highlights

·速生植物更有效地獲取和保留生物有效氮。

·較高的植物氮滯留與較高的根系生長(zhǎng)速率(RGR)相關(guān)。

·根系生長(zhǎng)速率越高的植物對(duì)土壤中氮的清除能力越強(qiáng)。

·礦物相關(guān)有機(jī)質(zhì)對(duì)氮的保留與根系生長(zhǎng)速率呈正相關(guān)。

Abstract

土地轉(zhuǎn)換對(duì)稻田土壤碳礦化的影響已受到越來(lái)越多的關(guān)注，但土壤微多樣性和化學(xué)多樣性在這一過(guò)程中的耦合作用尚不清楚。為了解決這一問(wèn)題，本研究以稻田（PF）為研究對(duì)象，以菜地（VF）、稻菜輪作（RV）和撂荒地（AL）為研究對(duì)象。分析了土壤礦化特征與微生物群落、代謝生理和可溶性有機(jī)質(zhì)（DOM）化學(xué)多樣性的關(guān)系。轉(zhuǎn)化后，AL和RV土壤礦化增強(qiáng)，分別是PF的217.49%和183.02%，而VF無(wú)明顯變化，但厭氧環(huán)境轉(zhuǎn)變?yōu)楹醚醐h(huán)境，土壤真菌豐富度/多樣性增加。這是因?yàn)橥寥赖V化直接受DOM數(shù)量和微生物代謝活性碳的調(diào)控，間接受DOM化學(xué)多樣性和微生物群落的調(diào)控。AL具有最大的DOC含量、最大的親水物質(zhì)（如羧基、碳水化合物和氨基）和豐富的富營(yíng)養(yǎng)類(lèi)群（如放線菌門(mén)和變形菌門(mén)）。VF無(wú)顯著變化主要與土壤中濃縮的芳香烴和寡營(yíng)養(yǎng)微生物增多、DOC減少有關(guān)，導(dǎo)致土壤頑固性碳的微生物代謝占主導(dǎo)地位。RV也存在頑固的碳代謝。而RV具有較高的生物利用度和適宜的DOM，表現(xiàn)出適度的土壤礦化。綜上所述，研究結(jié)果從微觀化學(xué)多樣性的角度提供了土地轉(zhuǎn)換對(duì)土壤礦化影響的分子視角，凸顯了養(yǎng)分供應(yīng)和微生物代謝策略的重要性。

Fig. 1.?Biplot of plant traits resulting from the PCA. The orange points stand for legume species, the springgreen stand for forb species, and the darkgreen stand for grass species. RAD, root area density (cm2?kg?1); RD, root diameter (mm); RGR, root growth rate (g m?2?day?1); RL, root lifespan (day); RLD, root length density (m kg?1); RTD, root tissue density (mg mm?3); SGR, shoot growth rate (g m?2?day?1); SLA, specific leaf area (mm2?mg?1); SRL, specific root length (cm mg?1).

Fig. 2.?Box plot of the?15N tracer retention by the (a) plant-soil systems, (b) shoots, (c) roots, (d) particulate organic matter (POM), and (e) mineral associated organic matter (MAOM). The?15N retention was given as percent of the?15N retained by a given component to total added?15N. The span of the box in the violin is the first to third quartile, the horizontal line inside the boxes is the median of samples, and black dots represent outliers.

?

?

Table 1.?The?15N tracer allocation (%) in shoots, roots, particulate organic matter (POM), and mineral associated organic matter (MAOM), given as the relative?15N retention by a given component with respect to total?15N retention.

Data are expressed as means?±?SE (n?=?5). Different letters indicate significant differences among species.

?

Fig. 3.?The relative importance metrics of plant functional traits as predictors of the?15N tracer retention (a-c), and its relationship with root growth rate and root lifespan (d-f). The error bars show 95?% confidence intervals. The red stars indicate the coefficient of the factor in multiple linear regression is significant. Note that the?P?value and R2?(marginal) in (e) were drawn from linear mixed model with species as a random effect (see methods). The orange points stand for legume species, the springgreen stand for forb species, and the darkgreen stand for grass species. Different point shapes stand for different species (see?Fig. 1). *?P?<?0.05; ***?P?<?0.001.

?

Fig. 4.?Relationships between the?15N tracer retention by plants (a) and plant-soil systems (b) and rhizosphere priming effects. The orange points stand for legume species, the springgreen stand for forb species, and the darkgreen stand for grass species. Different point shapes stand for different species (see?Fig. 1). RPE_POM, rhizosphere priming effects on native particulate organic matter decomposition; RPE_MAOM, rhizosphere priming effects on native mineral-associated organic matter decomposition.

?

?

Fig. 5.?The relative ability of plant N scavenging and its drivers. (a) The relative N scavenging ability of plants for each species, determined as the ratio of the?15N tracer retention by plants to rhizosphere priming effects. Bars are means?±?SE (n?=?5 except for?M. ruthenica?with n?=?3). Different letters indicate significant differences among means. (b) The relative importance metrics of plant functional traits as predictors of the relative N scavenging ability of plants. The error bars show 95?% confidence intervals. The red stars indicate the coefficient of the factor in multiple linear regression is significant (P?<?0.05). The relationships of the relative N scavenging ability of plants with plant C:N (c), and root growth rate (d). The orange points stand for legume species, the springgreen stand for forb species, and the darkgreen stand for grass species. Different point shapes stand for different species (see?Fig. 1).