scholarly journals Shifts in Leaf and Branch Elemental Compositions of Pinus massoniana (Lamb.) Following Three-Year Rainfall Exclusion

Forests ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 113
Author(s):  
Tian Lin ◽  
Xuan Fang ◽  
Yongru Lai ◽  
Huaizhou Zheng ◽  
Jinmao Zhu

We investigated changes in leaf and branch stoichiometry of Pinus massoniana caused by seasonal variation and experimental drought in response to a three-year manipulation of the rainfall exclusion. The results showed that (1) in response to rainfall exclusion manipulation, plant capacity to regulate leaf potassium (K) concentrations were notably lower than for leaf nitrogen (N) and phosphorus (P) concentrations. Thus, the plants modulated leaf N and P concentrations to improve water use efficiency, which take part in drought resistance mechanisms. Leaf K concentrations decreased continuously, having additional indirect negative effects on plant fitness. (2) The effects of seasonal variation on both the leaf K and P concentrations were significantly stronger than on leaf N concentrations. High leaf N and P concentrations and a low N:P ratio in the growing season improved the growth rate. (3) Principal component analyses (PCA) revealed that to adapt to drought, the plants regulated nutrient elements and then maintained certain stoichiometries as a capital to resist stress. Our results suggest that, on nutrient-poor soils, a lack of N or P (or both) would probably impede P. massoniana’s response to drought.

Forests ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 945 ◽  
Author(s):  
Ran Tong ◽  
Benzhi Zhou ◽  
Lina Jiang ◽  
Xiaogai Ge ◽  
Yonghui Cao ◽  
...  

Leaf nitrogen (N) and phosphorus (P) stoichiometry at a large geographical scale is the result of long-term adaptation to the environment. Therefore, the patterns of leaf N and P spatial distributions and their controlling factors represent an important issue in current ecological research. To explore the leaf stoichiometry of Chinese fir at a national level, we conducted a meta-analysis based on the dataset of the leaf nitrogen (N) and phosphorus (P) concentrations and the N:P ratio from 28 study sites across China. For all of the age groups considered, the average concentrations of the leaf N and P concentrations and the N:P ratio were 11.94 mg g−1, 1.04 mg g−1, and 12.93, respectively. Significant differences were found in the leaf P concentration and N:P ratio between the five age groups, while the differences in the leaf N concentration between the groups were not significant. Linear fitting results indicated that the leaf P concentration decreased, and the leaf N:P ratio increased with the increase of the MAT (mean annual temperature) and soil N concentration. Redundancy analysis (RDA) revealed that the first axis, with an explanatory quantity of 0.350, indicated that the MAT (mean annual temperature), soil nitrogen concentration and stand age had a good relationship with the leaf P concentration and N:P ratio, while the second axis, with an explanatory quantity of 0.058, indicated that the leaf N concentration was less affected by the environmental factors. These results demonstrate that the leaf P concentration and N:P ratio are affected by the stand age, an uneven distribution of the heat and soil nutrient concentration status, and N, as the limiting element, remaining relatively stable. Overall, our findings revealed the response of leaf stoichiometric traits to environment change, which benefits the management of Chinese fir plantations.


2020 ◽  
Author(s):  
Glaucia Soares Tolentino ◽  
Cristina Máguas ◽  
Luiz Fernando Silva Magnago ◽  
Tillmann Buttschardt ◽  
João Augusto Alves Meira-Neto

AbstractWoody plants in the Cerrado have been understood to comprise two groups: calcicole species responding to soil Al-Ca gradient (CAL) and leguminous species responding to inorganic soil N gradient (LEG). However, the bulk of Cerrado woody flora was not inside these groups. Our main question was whether CAL and LEG are distinct from each other as well as from the bulk of Cerrado species that occur rather in savannas than in quasi-forests (SAV) while responding only to soil variables and light. We performed the study among five soil categories, and measured canopy openness. We evaluated the functional traits of the 34 most relevant species of the studied Cerrado. We measured specific leaf area, bark thickness, leaf nitrogen, leaf carbon, leaf C/N, maximum height, maximum, stem elongation, δ15N and δ13C. We determined wood density by consulting a database. RLQ and Fouth-corner analyses confirmed CAL and LEG as consistent groups as well as found a third group, the SAV. CAL and LEG were found to dominate plots with low canopy openness; only CAL were negatively associated with aluminium saturation; only LEG were negatively associated with pH; only SAV were negatively associated with inorganic nitrogen and CEC. LEG presented the lowest leaf C/N and the highest leaf N meanwhile SAV presented the highest C/N, the lowest leaf N and the lowest stem elongation. Higher values of δ13C in leaves suggest higher water use efficiency for CAL and LEG than for SAV.


2016 ◽  
Vol 113 (15) ◽  
pp. 4098-4103 ◽  
Author(s):  
Mark Andrew Adams ◽  
Tarryn L. Turnbull ◽  
Janet I. Sprent ◽  
Nina Buchmann

Using robust, pairwise comparisons and a global dataset, we show that nitrogen concentration per unit leaf mass for nitrogen-fixing plants (N2FP; mainly legumes plus some actinorhizal species) in nonagricultural ecosystems is universally greater (43–100%) than that for other plants (OP). This difference is maintained across Koppen climate zones and growth forms and strongest in the wet tropics and within deciduous angiosperms. N2FP mostly show a similar advantage over OP in nitrogen per leaf area (Narea), even in arid climates, despite diazotrophy being sensitive to drought. We also show that, for most N2FP, carbon fixation by photosynthesis (Asat) and stomatal conductance (gs) are not related to Narea—in distinct challenge to current theories that place the leaf nitrogen–Asat relationship at the center of explanations of plant fitness and competitive ability. Among N2FP, only forbs displayed an Narea–gs relationship similar to that for OP, whereas intrinsic water use efficiency (WUEi; Asat/gs) was positively related to Narea for woody N2FP. Enhanced foliar nitrogen (relative to OP) contributes strongly to other evolutionarily advantageous attributes of legumes, such as seed nitrogen and herbivore defense. These alternate explanations of clear differences in leaf N between N2FP and OP have significant implications (e.g., for global models of carbon fluxes based on relationships between leaf N and Asat). Combined, greater WUE and leaf nitrogen—in a variety of forms—enhance fitness and survival of genomes of N2FP, particularly in arid and semiarid climates.


2012 ◽  
Vol 60 (1) ◽  
pp. 61 ◽  
Author(s):  
Jun-Tao Zhu ◽  
Xiang-Yi Li ◽  
Xi-Ming Zhang ◽  
Qiang Yu ◽  
Li-Sha Lin

Groundwater-dependent vegetation (GDV) is useful as an indicator of watertable depth and water availability in north-western China. Nitrogen (N) is an essential limiting resource for growth of GDV. To elucidate how leaf N allocation and partitioning influence photosynthesis and photosynthetic N-use efficiency (PNUE), three typical GDV species were selected, and their photosynthesis, leaf N allocation and partitioning were investigated in the Taklamakan Desert. The results showed that Karelinia caspica (Pall.) Less. and Peganum harmala L. had lower leaf N content, and allocated a lower fraction of leaf N to photosynthesis. However, they were more efficient in photosynthetic N partitioning among photosynthetic components. They partitioned a higher fraction of the photosynthetic N to carboxylation and showed higher PNUE, whereas Alhagi sparsifolia Shap. partitioned a higher fraction of the photosynthetic N to light-harvesting components. For K. caspica and P. harmala, the higher fraction of leaf N was allocated to carboxylation and bioenergetics, which led to a higher maximum net photosynthetic rate, and therefore to a higher PNUE, water-use efficiency (WUE), respiration efficiency (RE) and so on. In the desert, N and water are limiting resources; K. caspica and P. harmala can benefit from the increased PNUE and WUE. These physiological advantages and their higher leaf-area ratio (LAR) may contribute to their higher resource-capture ability.


Atmosphere ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 526
Author(s):  
Tianming Sun ◽  
Rui Li ◽  
Ya Meng ◽  
Yu Han ◽  
Hanyun Cheng ◽  
...  

Humic-like substances (HULIS) are of great interest due to their optical and chemical characteristics. In this study, a total of 180 samples of atmospheric particulate matter (PM) of different sizes were collected from summer 2018 to spring 2019, in order to analyze the size distribution, to investigate the seasonal variation and then to identify the key sources of HULIS. The annual mean concentration of HULIS in the total suspended particulates reached 5.12 ± 1.42 μg/m3. The HULIS concentration was extremely higher in winter (8.35 ± 2.06 μg/m3) than in autumn (4.88 ± 0.95 μg/m3), in summer (3.62 ± 1.68 μg/m3) and in spring (3.36 ± 0.99 μg/m3). The average annual ratio of water-soluble organic carbon (WSOC) to OC and the ratio of HULIS to WSOC reached 0.546 ± 0.092 and 0.56 ± 0.06, respectively. Throughout the whole year, the size distributions of WSOC and HULIS-C were relatively smooth. The peaks of WSOC appeared at 1.8~3.2 μm and 0.56~1.0 μm, while the peaks of HULIS-C were located at 3.2~5.6 μm, 1.0~1.8 μm and 0.18~0.32 μm. The distribution of the HULIS particle mode was similar in spring, summer and autumn, while there was a lower proportion of the coarse mode and a higher proportion of the condensation mode in winter. By using the comprehensive analysis of principal component analysis (PCA), air mass backward trajectories (AMBTs) and fire point maps, key sources of WSOC and HULIS in Shanghai were identified as biomass combustion (48.42%), coal combustion (17.49%), secondary formation (16.07%) and vehicle exhaust (5.37%). The remaining part might be contributed by crustal dust sources, marine sources and/or other possible sources. This study provides new insight into the characteristics and size distribution of HULIS in Shanghai, thereby providing a practical base for further modeling.


Heliyon ◽  
2020 ◽  
Vol 6 (12) ◽  
pp. e05718
Author(s):  
Md. Akhter Hossain Chowdhury ◽  
Taslima Sultana ◽  
Md. Arifur Rahman ◽  
Tanzin Chowdhury ◽  
Christian Ebere Enyoh ◽  
...  

Author(s):  
Iqra Ghafoor ◽  
Muhammad Habib-ur-Rahman ◽  
Muqarrab Ali ◽  
Muhammad Afzal ◽  
Wazir Ahmed ◽  
...  

AbstractHigher demands of food led to higher nitrogen application to promote cropping intensification and produce more which may have negative effects on the environment and lead to pollution. While sustainable wheat production is under threat due to low soil fertility and organic matter due to nutrient degradation at high temperatures in the region. The current research explores the effects of different types of coated urea fertilizers and their rates on wheat crop under arid climatic conditions of Pakistan. Enhancing nitrogen use efficiency by using eco-friendly coated urea products could benefit growers and reduce environmental negative effects. A trial treatment included N rates (130, 117, 104, and 94 kg ha-1) and coated urea sources (neem coated, sulfur coated, bioactive sulfur coated) applied with equal quantity following split application method at sowing, 20 and 60 days after sowing (DAS). The research was arranged in a split-plot design with randomized complete block design had three replicates. Data revealed that bioactive sulfur coated urea with the application of 130 kg N ha-1 increased chlorophyll contents 55.0 (unit value), net leaf photosynthetic rate (12.51 μmol CO2 m-2 s-1), and leaf area index (5.67) significantly. Furthermore, research elucidates that bioactive sulfur urea with the same N increased partial factor productivity (43.85 Kg grain Kg-1 N supplied), nitrogen harvest index (NHI) 64.70%, and partial nutrient balance (1.41 Kg grain N content Kg-1 N supplied). The neem-coated and sulfur-coated fertilizers also showed better results than monotypic urea. The wheat growth and phenology significantly improved by using coated fertilizers. The crop reached maturity earlier with the application of bioactive sulfur-coated urea than others. Maximum total dry matter 14402 (kg ha-1) recorded with 130 kg N ha-1application. Higher 1000-grain weight (33.66 g), more number of grains per spike (53.67), grain yield (4457 kg ha-1), and harvest index (34.29%) were obtained with optimum N application 130 kg ha-1 (recommended). There is a significant correlation observed for growth, yield, and physiological parameters with N in the soil while nitrogen-related indices are also positively correlated. The major problem of groundwater contamination with nitrate leaching is also reduced by using coated fertilizers. Minimum nitrate concentration (7.37 and 8.77 kg ha-1) was observed with the application of bioactive sulfur-coated and sulfur-coated urea with lower N (94 kg ha-1), respectively. The bioactive sulfur-coated urea with the application of 130 kg N ha-1 showed maximum phosphorus 5.45 mg kg-1 and potassium 100.67 mg kg-1 in the soil. Maximum nitrogen uptake (88.20 kg ha-1) is showed by bioactive sulfur coated urea with 130 kg N ha-1 application. The total available NPK concentrations in soil showed a significant correlation with physiological attributes; grain yield; harvest index; and nitrogen use efficiency components, i.e., partial factor productivity, partial nutrient balance, and nitrogen harvest index. This research reveals that coating urea with secondary nutrients, neem oil, and microbes are highly effective techniques for enhancing fertilizer use efficiency and wheat production in calcareous soils and reduced N losses under arid environments.


Agronomy ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 99
Author(s):  
Surendra Kumar Meena ◽  
Renu Pandey ◽  
Sandeep Sharma ◽  
Gayacharan ◽  
Tarun Kumar ◽  
...  

To understand the physiological basis of tolerance to combined stresses to low phosphorus (P) and drought in mungbean (Vignaradiata (L.) R. Wilczek), a diverse set of 100 accessions were evaluated in hydroponics at sufficient (250 μM) and low (3 μM) P and exposed to drought (dehydration) stress. The principal component analysis and ranking of accessions based on relative values revealed that IC280489, EC397142, IC76415, IC333090, IC507340, and IC121316 performed superior while IC119005, IC73401, IC488526, and IC325853 performed poorly in all treatments. Selected accessions were evaluated in soil under control (sufficient P, irrigated), low P (without P, irrigated), drought (sufficient P, withholding irrigation), and combined stress (low P, withholding irrigation). Under combined stress, a significant reduction in gas exchange traits (photosynthesis, stomatal conductance, transpiration, instantaneous water use efficiency) and P uptake in seed and shoot was observed under combined stress as compared to individual stresses. Among accessions, IC488526 was most sensitive while IC333090 and IC507340 exhibited tolerance to individual or combined stress. The water balance and low P adaptation traits like membrane stability index, relative water content, specific leaf weight, organic acid exudation, biomass, grain yield, and P uptake can be used as physiological markers to evaluate for agronomic performance. Accessions with considerable tolerance to low P and drought stress can be either used as ‘donors’ in Vigna breeding program or cultivated in areas with limited P and water availability or both.


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