Effects of tree size and organ age on variations in carbon,nitrogen,and phosphorus stoichiometry in Pinus koraiensis

Carbon(C),nitrogen(N),and phosphorus(P)are of fundamental importance for growth and nutrient dynamics within plant organs and deserve more attention at regional to global scales.However,our knowledge of how these nutrients vary with tree size,organ age,or root order at the individual level remains limited.We determined C,N,and P contents and their stoichiometric ratios(i.e.,nutrient traits)in needles,branches,and fine roots at different organ ages(0-3-year-old needles and branches)and root orders(1st-4th order roots)from 64 Pinus koraiensis of varying size(Diameter at breast height ranged from 0.3 to 100 cm)in northeast China.Soil factors were also measured.The results show that nutrient traits were regulated by tree size,organ age,or root order rather than soil factors.At a whole-plant level,nutrient traits decreased in needles and fine roots but increased in branches with tree size.At the organ level,age or root order had a negative effect on C,N,and P and a positive effect on stoichiometric ratios.Our results demonstrate that nutrient variations are closely related to organ-specific functions and ecophysiological processes at an individual level.It is suggested that the nutrient acquisition strategy by younger trees and organ fractions with higher nutrient content is for survival.Conversely,nutrient storage strategy in older trees and organ fractions are mainly for steady growth.Our results clarified the nutrient utilization strategies during tree and organ ontogeny and suggest that tree size and organ age or root order should be simultaneously considered to understand the complexities of nutrient variations.

Macronutrients Uptake in Soybean as Affected by <i>Bradyrhizobium japonicum</i>Inoculation and Phosphorus (P) Supplements

Field and glasshouse experiments were conducted to study the effect of B. japonicum inoculation and phosphorus supplementation on macronutrient uptake by soybean. The treatments consisted of B. japonicum inoculation (with & without), phosphorus supplementation at the levels of 0, 20, 40 and 80 kg P·ha-1. Both treatments were replicated four times in a split plot design. The macronutrients considered were N, P, K, Ca and Mg. Results showed that inoculation with B. japonicum significantly contribute to the uptake of N, P, K, Ca and Mg in roots, shoots, pods and the whole soybean plant. Likewise, phosphorus supplementation significantly enhanced the uptake of N, P, K, Ca and Mg in roots, shoots, pods and the whole plant. The use of effective strains of rhizobia and P supplementation was an effective way of enhancing the growth of soybean, eventually the uptake of macronutrients in plant organs.

植物N/P与土壤pH值对湿地植物物种丰富度的影响

通过人工控制模拟试验,研究了植物中全氮与全磷之比（植物N/P）和土壤pH值与湿地植物物种丰富度的关系.结果表明,湿地物种丰富度与植物N/P之间呈单峰变化关系,当2.0〈N/P〈9.5,物种丰富度随着N/P的增加而增加;当N/P约等于9.5时,氮、磷的有效性达到平衡,物种丰富度最高;N/P〉9.5时,氮、磷供应平衡系统可能被破坏,湿地物种逐渐减少.物种丰富度与土壤pH值表现为显著的正相关关系（R^2=0.526）,当pH值为5.6～6.8时,物种丰富度随着土壤pH值增加而增加.通过方差分析,土壤pH值和植物N/P对物种丰富度的影响分别为37.96%和15.29%.

Improvement of Water and Wastewater Treatment Process Using Various Sound Waves—A Consideration from the Viewpoint of Frequency

Application of sound waves is one of the novel techniques for the improvement of water treatment process. In this study, various sound waves such as 1) ultrasonic wave, 2) music box, and 3) windbell were irradiated to water and wastewater for removing contaminants such as nitrate, phosphorus and BOD/COD. As a result, a possibility of improvement of water and wastewater treatment process using sound waves with various frequencies was proposed.

The Effects of Legume Crops （Pea and Faba Bean） on Soil Nutrients Availability and Yield Parameters of Subsequent Cabbage Crops under Organic Production Conditions

Three equal field plots were cultivated with respectively wheat, field pea and faba bean. The common conventional production technology, including the use of chemical fertilizers was applied in wheat, but no fertilizers at all were used in faba bean and field pea plots. Atter legume harvesting, forty day old broccoli and cauliflower seedlings were transplanted to each of them according to three replications randomized block design. The transplanting was conducted at equal planting density, and common organic production practices were applied in entire production cycle. The legume crops improved soil fertility by increasing total soil N （Nitrogen） and improving P （Phosphorus） and K （Potassium） availability to the subsequent crops. As a result, an enhanced vegetative growth, improved curd setting and increased average curd weight was found in broccoli and cauliflower. However, there were significant differences between legume crops themselves regarding the proved benefits to the subsequent crops, confirming a clear advantage of faba bean versus field pea. A significantly higher above ground biomass was recorded in cauliflower plants followed faba bean, compared with field pea and wheat, but no difference was found regarding the biomass production in broccoli. The higher percentage of plants set curds （either broccoli or cauliflower） was obtained in the variants followed faba bean and then field pea. The same was true regarding total curd yield and the average curd weight for both： broccoli and cauliflower.

氮磷养分介导的植物–微生物互作研究进展

氮、磷是植物生长发育所必需的大量营养元素,植物对氮磷养分的高效吸收利用与外界环境密切相关,同时氮磷养分又会影响植物的环境适应性。为此,植物如何整合适应不同的外部环境,特别是生物环境,以实现氮磷养分的高效吸收利用,是植物营养研究领域的前沿新热点。本文对近年来氮磷养分介导的植物-微生物互作研究进展进行综述,主要涉及氮磷养分介导的有益和有害生物互作研究,阐释了氮磷核心转录调控因子NLPs和PHRs在调控植物-微生物互作过程中的重要作用,总结了植物体内磷素感受蛋白SPXs在调控植物-微生物互作过程中的功能多样性。此外,本文还对未来氮磷养分介导的植物-微生物互作研究的关键点进行了展望。

Family-level leaf nitrogen and phosphorus stoichiometry of global terrestrial plants

Leaf nitrogen(N) and phosphorus(P) concentrations are critical for photosynthesis, growth, reproduction and other ecological processes of plants. Previous studies on large-scale biogeographic patterns of leaf N and P stoichiometric relationships were mostly conducted using data pooled across taxa, while family/genus-level analyses are rarely reported. Here, we examined global patterns of family-specific leaf N and P stoichiometry using a global data set of 12,716 paired leaf N and P records which includes 204 families, 1,305 genera, and 3,420 species. After determining the minimum size of samples(i.e., 35 records), we analyzed leaf N and P concentrations, N:P ratios and N^P scaling relationships of plants for 62 families with 11,440 records. The numeric values of leaf N and P stoichiometry varied significantly across families and showed diverse trends along gradients of mean annual temperature(MAT) and mean annual precipitation(MAP). The leaf N and P concentrations and N:P ratios of 62 families ranged from 6.11 to 30.30 mg g–1, 0.27 to 2.17 mg g–1, and 10.20 to 35.40, respectively. Approximately 1/3–1/2 of the families(22–35 of 62) showed a decrease in leaf N and P concentrations and N:P ratios with increasing MAT or MAP, while the remainder either did not show a significant trend or presented the opposite pattern. Family-specific leaf N^P scaling exponents did not converge to a certain empirical value, with a range of 0.307–0.991 for 54 out of 62 families which indicated a significant N^P scaling relationship. Our results for the first time revealed large variation in the family-level leaf N and P stoichiometry of global terrestrial plants and that the stoichiometric relationships for at least one-third of the families were not consistent with the global trends reported previously. The numeric values of the family-specific leaf N and P stoichiometry documented in the current study provide critical synthetic parameters for biogeographic modeling and for further studies on the physiological and ecological mechanisms underlying the nutrient use strategies of plants from different phylogenetic taxa.

Phosphorus and Nitrogen Interactions in Field-Grown Soybean as Related to Genetic Attributes of Root Morphological and Nodular Traits

Two field experiments with different soybean (Glycine max L.) materials were conducted to investigate the interactions between phosphorus (P) and nitrogen (N) as related to the genetic attributes of root morphological and nodular traits. In experiment one, 13 cultivated soybean varieties were grown in a field with relatively low soil P and N availability. P application with 160 kg P/hm2 as triple superphosphate produced a significant simultaneous increase in the content of both P and N in shoot, demonstrating positive P and N interactions. The addition of P also increased root dry weight, root nodule number, nodule mass, nodule size, and nodulation index, but decreased root length and root surface area, indicating that P may affect N nutrition in soybean through a number of root morphological and nodular traits. Interestingly, like P content, N content appeared to be more correlated with root morphological traits (root weight, root length, and root surface area) than with root nodular traits (nodule number, nodule size, nodule mass, and nodulation index) at both P levels, implying that N taken up by the roots may contribute more to the plant N status than biological N2 fixation under the present experimental conditions. In experiment two, 57 soybean lines of a recombinant inbred line (RIL) population derived from a cross between a cultivated variety and a wild genotype were grown on another field site with moderately sufficient P and N levels to further characterize the genetic attributes of root morphological and nodular traits and their relationships with P and N interactions. The results indicated that all morphological and nodular traits measured continually segregated in the RIL population with a normal distribution of the phenotypic values, indicating that these traits are possibly controlled by quantitative trait loci (QTLs). Genetic analysis revealed that all these root traits had relatively low heritabilities (h2b=74.12,70.65,73.76,56.34,52.59, and 52.24 for root weight, root length, root surface area, nodule number, nodule mass, and nodule size, respectively), suggesting that root morphology and nodule formation are influenced greatly by environmental factors. Correlation analysis of the RILs showed that shoot N content was significantly correlated with P content, confirming positive PXN interactions. Similar to experiment one, shoot N content was only significantly correlated with root morphological traits, but not with root nodular traits, again denoting the fact that the N status in soybean could be attributed more to N uptake from the soil than to biological N2 fixation under the present experimental conditions.

Divergent responses of plant biomass and diversity to short-term nitrogen and phosphorus addition in three types of steppe in Inner Mongolia,China

Background:Understanding the response of the plant community to increasing nitrogen(N)and phosphorus(P)inputs is helpful for managing and protecting grassland ecosystems in semiarid areas.However,information about different types of steppe responses to N and P availability in semiarid grasslands is limited.In 2017-2018,two field experiments were conducted with six levels of N(from 5 to 30 g N m^(−2)yr^(−1))and P(from 2.5 g to 15 g P m^(−2)yr^(−1))additions in three different temperate steppes,including meadow steppe(MS),typical steppe(TS),and desert steppe(DS),in northern China to study the effects of these addition rates on community biomass and diversity.Results:Our results showed that plant biomass and diversity in the three steppe types in Inner Mongolia responded differently to elevated N and P inputs.Increasing P promoted aboveground and belowground biomass more than increasing N in the three temperate steppes.Short-term N and P additions reduced plant diversity to some extent,with the most pronounced decreases in MS and DS.It is noteworthy that there were response thresholds for plant diversity and biomass in response to N and P inputs in different steppe types(e.g.,10 g P m^(−2)yr^(−1)).Furthermore,redundancy analysis and stepwise regression analysis revealed that changes in soil properties induced by nutrient addition and climate conditions jointly regulated changes in vegetation biomass and diversity.Conclusions:The plant biomass and diversity of three steppe types in Inner Mongolia respond divergently to elevated N and P inputs.Our results indicate that regional differences in climate and soil substrate conditions may jointly contribute to the divergent responses of plant biomass and diversity to short-term N and P addition.Our analyses provide new insights into managing and protecting grassland ecosystems.Considering that the effects of nutrient addition on plant diversity and productivity may have increasing effects over time,studies on long-term in situ nutrient addition are necessary.

Seed nutrient is more stable than leaf in response to changing multiple resources in an alpine meadow

Background It has been long thought that nitrogen(N),phosphorus(P)concentrations and their ratios(N:P)in metabolically active or functional organs(i.e.,leaves)are less responsive to environmental changes.Little attention,however,has been paid to the reproductive organs-seeds,while seeds may maintain their nutrients more stable for the evolutionary fitness of next generation.Methods Here,we conducted a field experiment of N,P addition and drought in an alpine meadow,aiming to compare the difference of leaf and seed nutrients and stoichiometric ratios in response to these resource treatments and their interactions.Four dominant species were selected among grass and forb functional groups,including Elymus nutans,Deschampsia caespitosa,Artemisia roxburghiana and Polygonum viviparum.Results Under natural conditions,leaf N and P concentrations were consistently lower than seed among species.However,leaf nutrients were much more sensitive than seed nutrients to N and P addition.Specifically,N or P addition accordingly increased leaf N or P concentration by 22.20-44.24%and 85.54-93.61%,while only enhanced seed N or P concentration by 5.15-17.20%and 15.17-32.72%,respectively.Leaf N or P concentration was significantly reduced by P or N addition,but seed nutrients remained unchanged.In contrast,drought did not change both organ nutrients.Similarly,nutrient addition and drought had synergistic interactions on leaf nutrients,but not on seed nutrients.Conclusions This study highlights that seed nutrient concentrations could be more stable than metabolically active leaf organ when facing multidimensional resource changes.This complements the traditional view on the‘Stable Leaf Nutrient Hypothesis’with the involvement of reproductive organs.The less responsiveness of seed nutrients suggests the adaptive strategy to ensure the success of next generations and long-term plant demographic stability.

黄土丘陵区草地群落多样性和优势种养分对氮添加的响应

为探究大气氮沉降对黄土丘陵区草地群落多样性及其优势种生长的影响,本研究以白羊草(Bothriochloa ischaemum,Bi)和达乌里胡枝子(Lespedeza davurica,Ld)为优势种的草地群落为研究对象,设置3个氮添加处理(N0,0 kg·hm^(-2)·a^(-1);N25,25 kg·hm^(-2)·a^(-1);N75,75 kg·hm^(-2)·a^(-1)),测定并分析了白羊草和达乌里胡枝子的株高、盖度、地上生物量(Aboveground biomass,AGB),物种多样性和养分含量。结果表明:氮添加处理下,Bi和Ld群落的总AGB显著提高;Bi群落中,氮添加显著降低物种多样性指数,而显著提高白羊草的全氮含量和氮磷比;Ld群落中,氮添加显著增加物种多样性指数,而显著降低达乌里胡枝子的全氮含量和氮磷比;相关性分析表明,物种多样性与白羊草的盖度和生物量呈显著负相关关系,与达乌里胡枝子的高度、盖度和AGB呈显著正相关。综上,氮添加促进了白羊草生长但抑制达乌里胡枝子,其群落优势种的AGB对物种多样性影响更加重要。

Human-driven global nutrient imbalances increase risks to health

Human-induced inputs of nitrogen(N)and phosphorus(P)into the biosphere have reached unprecedented levels,particularly N,leading to an escalating global anthropogenic N:P ratio.This ratio has emerged as a significant driver of environmental change,impacting organisms,ecosystems,and global food security.However,the implications of this ratio for human health have been largely overlooked and remain uncertain.This article aims to fill this knowledge gap by exploring the potential effects of N:P ratios on both non-infectious and infectious diseases.Preliminary data emphasize the importance of investigating the influence of N:P ratios on human health,suggesting a potential role in the rise of non-infectious diseases,such as cancer,as well as the proliferation of infectious diseases,including Zika and malaria.These findings highlight the urgent need for increased attention from the scientific community and policymakers regarding the complex impacts of the human-induced biospheric N:P ratio.It is crucial to investigate and understand the underlying mechanisms and drivers behind these effects.Furthermore,there is significant potential for improving human health through the manipulation of N:P ratios and the availability of N and P.This applies not only to medical treatments but also to innovative fertilizer management strategies.These avenues present promising opportunities to address the challenges associated with human health in an ever-changing world.

合肥城区地表灰尘氮磷形态分布及生物有效性

为了解合肥市城区地表灰尘氮磷形态分布特征及其生物有效性,在城市不同功能用地的不透水地面采集52份灰尘样品.利用化学提取方法,分析测得氨氮(NH4+-N)、硝酸盐氮(NO3--N)、易交换态磷(Ex-P)、铝结合态磷(Al-P)、铁结合态磷(Fe-P)、闭蓄态磷(Oc-P)、钙结合态磷(Ca-P)、碎屑磷(De-P)和有机磷(Or-P)等各形态氮磷及总氮(TN)和总磷(TP)含量.在此基础上,开展各形态氮磷的空间分布特征、相关关系及生物有效性分析.结果表明,合肥市地表灰尘中氮的主要组成为有机氮(Or-N)、磷的主要组分为无机磷(IP);各形态氮和磷的空间分布受城市土地利用类型影响较大,部分氮磷形态表现出了较为显著的相关性;在工业区、商业区、居住区、文教区、交通区和公园绿地等功能区,生物有效性氮含量分别占TN的质量分数为8.87%、9.60%、6.68%、9.37%、8.20%和8.17%,生物有效性磷含量分别占TP的质量分数为6.70%、18.19%、10.10%、9.69%、10.64%和14.03%.