Growth strategies as determinants of CO2 sequestration and response to nitrogen fertilisation in C4 grasses in South American natural grasslands

2020 ◽  
Vol 71 (8) ◽  
pp. 776
Author(s):  
Anderson Cesar Ramos Marques ◽  
Leandro Bittencourt de Oliveira ◽  
Raíssa Schwalbert ◽  
Bianca Knebel Del Frari ◽  
Gustavo Brunetto ◽  
...  
Keyword(s):  
Leaf Area ◽  
Resource Conservation ◽  
Co2 Assimilation ◽  
Growth Strategy ◽  
Grass Species ◽  
South American ◽  
N Addition ◽  
Growth Strategies ◽  
Resource Capture ◽  
Natural Grasslands

Grass species grown in South American natural grasslands present different growth strategies related to variations in specific leaf area (SLA), leaf dry matter content (LDMC) and possible nitrogen (N) allocation. Nitrogen fertilisation can have effects on physiological processes such as CO2 assimilation; however, these responses can change depending on the growth strategy adopted by each species. The aim of the present study is to determine the effects of N fertilisation on SLA, LDMC and CO2 assimilation in eight C4 grass species: Axonopus affinis, Paspalum pumilum, P. notatum, P. urvillei, P. plicatulum, Andropogon lateralis, Saccharum angustifolium and Aristida laevis. These species were cultivated in pots filled with soil subjected to two conditions of N availability: nil (control) and 200 mg N kg–1 soil. The SLA of Axonopus affinis was 5.4 times higher than that of Aristida laevis. Axonopus affinis and P. pumilum recorded the lowest LDMC, their leaves showed 53% lower LDMC than observed for Aristida laevis, on average. Resource-capture species showed variation in leaf area with N addition to values 20% higher than the control, whereas species characterised by a resource-conservation growth strategy recorded variation in leaf area with N addition to values only 8% higher than the control. With N addition, the CO2 assimilation of resource-capture species represented variation (increase) nine times that of resource-conservation species compared with their respective controls. Resource-capture species have greater CO2 capture potential than resource-conservation species, mainly a result of N addition.

scholarly journals Quantitative Evaluation of the Trade-Off Growth Strategies of Maize Leaves under Different Drought Severities

Water ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 1852
Author(s):  
Xueyan Ma ◽  
Guangsheng Zhou ◽  
Gen Li ◽  
Qiuling Wang
Keyword(s):  
Water Content ◽  
Leaf Area ◽  
Metabolic Activity ◽  
Leaf Traits ◽  
Specific Weight ◽  
Growth Strategy ◽  
Drought Severity ◽  
Leaf Water Content ◽  
Growth Strategies ◽  
Trade Off

The leaf is one of the most drought-sensitive plant organs. Investigating how leaf traits change and their trade-off growth during a drought would contribute to developing targeted drought-resistance measures. We investigated changes in five key maize leaf traits (leaf area, dry mass, effective number, water content, and specific weight) and their trade-off growth based on a drought simulation experiment. We also developed an indicator (0, 1) to quantitatively evaluate drought severity. The results showed a trade-off growth between different leaf traits of maize plants under drought conditions. Maize maintained relatively high leaf water content to maintain high leaf metabolic activity until drought severity was greater than 0. When drought severity was (0, 0.48), maize tended to adopt rapid growth strategy by maintaining regular leafing intensity and investing more energy into leaf area rather than specific leaf weight so that more energy could be absorbed. When the drought severity exceeded 0.48, maize conserved its resources for survival by maintaining relatively lower metabolic activity and thicker leaves to minimize water loss. The results provide an insight into the acclimation strategies of maize under drought, and contribute to targeted drought prevention and relief measures to reduce drought-induced risks to food security.

Determining the Performance of Five Ornamental Grasses under Reduced Moisture Conditions

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 491a-491
Author(s):  
James T. Cole ◽  
Janet C. Cole
Keyword(s):  
Leaf Area ◽  
Stomatal Resistance ◽  
Time Domain Reflectometry ◽  
Grass Species ◽  
Drought Period ◽  
Shoot Ratio ◽  
Relative Water ◽  
Moisture Conditions ◽  
Water Treatments ◽  
Potential Transpiration

An experiment was conducted to evaluate the performance of five ornamental grass species under reduced moisture. This experiment was conducted in the greenhouse with three water treatments for each species: 1) Well-watered plants were irrigated daily throughout the experiment, 2) acclimated-plants were exposed to four drought cycles prior to a final drought period in which measurements were taken, and 3) non-acclimated plants received daily irrigation until undergoing a drought cycle in which measurements were taken. A drought cycle was defined as the time from irrigation until Time Domain Reflectometry (TDR) measured 0 (zero). Preliminary observations determined the plants to be under severe stress, but capable of recovering at TDR measurements of 0. All plants were established from tillers of a single parent for each species. Two plants of each species for the three treatments were established in five blocks. Leaf water potential, osmotic potential, transpiration, stomatal resistance, and relative water content were measured during the drought cycle. At the end of the experiment the leaf area and root and shoot dry weights were determined, root to shoot ratio and leaf area ratio were calculated, and the plants were analyzed for macronutrient and micronutrient contents.

Taxonomic revision of the genus Panca Evans, 1955 (Hesperiidae: Hesperiinae: Hesperiini: Moncina) with the description of two new species

Zootaxa ◽  
2020 ◽  
Vol 4830 (3) ◽  
pp. 503-543
Author(s):  
ADALBERTO DANTAS DE MEDEIROS ◽  
DIEGO RODRIGO DOLIBAINA ◽  
EDUARDO CARNEIRO ◽  
OLAF HERMANN HENDRIK MIELKE ◽  
MIRNA MARTINS CASAGRANDE
Keyword(s):  
New Species ◽  
Taxonomic Revision ◽  
Minas Gerais ◽  
South American ◽  
Mato Grosso ◽  
Distribution Maps ◽  
Natural Grasslands ◽  
Two New Species ◽  
Distrito Federal ◽  
Respective Species

The South American genus Panca Evans, 1955 and its respective species are revised. Previous to this study, the genus included solely its type species, Lerodea subpunctuli Hayward, 1934, until Panca moseri Dolibaina, Carneiro & O. Mielke, 2017 was described recently. However, as a result of a broader morphological study including closely related genera, we here propose that Panca assembles 12 species, most of which inhabit open environments such as the Cerrado biome and the natural grasslands of the Atlantic Forest biome. Eight species formerly included among other genera of Moncina are here combined with Panca: Panca satyr (Evans, 1955) comb. nov., Panca tobiasi (Mielke, 1992) comb. nov., Panca trogon (Evans, 1955) comb. nov., Panca steinhauseri (Dolibaina & A. Warren, 2015) comb. nov., Panca acroleuca (Plötz, 1884) comb. nov., and Panca mirnae (O. Mielke, Dolibaina, Carneiro & A. Warren, 2015) comb. nov. (all formerly in Artines Godman, 1901), Panca paulo (Bell, 1932) comb. nov. (formerly in Eutocus Godman, 1901), and Panca mictra (Evans, 1955) comb. nov. (formerly in Vidius Evans, 1955). Additionally, two new species are described from Brazil: Panca puri Medeiros, O. Mielke & Casagrande sp. nov. (from Pará, Pernambuco, Minas Gerais, Rio de Janeiro and Paraná) and Panca xavante Medeiros, O. Mielke & Dolibaina sp. nov. (from Mato Grosso, Goiás, Distrito Federal and Minas Gerais). A neotype for Apaustus acroleuca Plötz, 1884 is designated. Illustrations of the male and female genitalia and distribution maps are presented for all the species of Panca and an identification key is provided for both sexes. 

scholarly journals Growth and Productivity Analysis of Micro Finance Sector: A Case Study of Pakistan

2019 ◽  
Vol IV (III) ◽  
pp. 71-79
Author(s):  
Adnan Ahmad ◽  
Muhammad Ilyas ◽  
Muhammad Nisar Khan
Keyword(s):  
Rural Areas ◽  
Urban Areas ◽  
Growth Strategy ◽  
Productivity Analysis ◽  
Growth Strategies ◽  
Physical Infrastructure ◽  
Different Types ◽  
The Government ◽  
Efficiency And Productivity

This study reviews the growth strategies and their effect on the efficiency and productivity of the microfinance sector of Pakistan. The sector needs to have adopted intensive growth strategy instead of extensive strategies of wide expansion in term of physical infrastructure and human resources, which had increased the financial sustainability risks for the credit constrain institutions. The sixdimension model of outreach used in this study also shows that the sector does not achieve the targets set forth for these micro finance institutes with respect to its active borrowers’ outreach. The sector has mainly focused the big cities and urban areas whereas the poverty levels are higher in rural areas. The government has also shown its interest by launching two different types of loan schemes. Among the three different types of institution, the microfinance banks dominate the sector.

scholarly journals The challenge of abandonment for the sustainable management of Palaearctic natural and semi-natural grasslands

Hacquetia ◽  
2018 ◽  
Vol 17 (1) ◽  
pp. 5-16 ◽  
Author(s):  
Orsolya Valkó ◽  
Stephen Venn ◽  
Michał Żmihorski ◽  
Idoia Biurrun ◽  
Rocco Labadessa ◽  
...  
Keyword(s):  
Sustainable Management ◽  
Grassland Management ◽  
Grass Species ◽  
Economic Changes ◽  
The Core ◽  
Natural Grasslands ◽  
Biomass Removal ◽  
Management Regimes ◽  
The Impact ◽  
Grassland Biodiversity

Abstract Disturbance by biomass removal is a crucial mechanism maintaining the diversity of Palaearctic grasslands, which are unique biodiversity hotspots. The century-long traditional land use of mowing, grazing and burning, has been fundamentally changed in many parts of the Palaearctic. Due to socio-economic changes, large areas of former pastures and meadows have been abandoned, leading to a succession towards secondary scrublands or forest and the encroachment of competitor grass species, all leading to a decrease in biodiversity. Here we report the causes and consequences of the cessation of traditional grassland management regimes, provide strategies for reducing the impact of abandonment and consider these from the perspective of sustainability. We consider the possibilities for initiating sustainable management regimes in the contemporary socio-economic environment, and discuss the prospects and limitation of alternative management regimes in the conservation of grassland biodiversity. These themes are also the core topics of this Special Feature, edited by the EDGG. We hope that this Special Feature will encourage steps towards more sustainable strategies for the conservation of Palaearctic grasslands and the integration of the sustainability perspective into their conservation.

Root, shoot and leaf traits of the congeneric Styrax species may explain their distribution patterns in the cerrado sensu lato areas in Brazil

2011 ◽  
Vol 38 (3) ◽  
pp. 209 ◽  
Author(s):  
Gustavo Habermann ◽  
Anna C. G. Bressan
Keyword(s):  
Leaf Area ◽  
Riparian Forest ◽  
Leaf Traits ◽  
Distribution Patterns ◽  
Co2 Assimilation ◽  
Sensu Stricto ◽  
Shoot Length ◽  
Deep Roots ◽  
Number Of Leaves ◽  
Forest Habitats

Shoot and root lengths, the number of leaves, biomass and leaf area were measured in Styrax ferrugineus Nees and Mart., Styrax camporum Pohl. and Styrax pohlii A. DC cultivated in rhizotrons. Additionally, young individuals of these species were planted in a cerrado sensu stricto (s. str.), at the edge and in the understorey of a cerradão, and in the understorey of a riparian forest. Six months after planting, the specific leaf area (SLA) and the CO2 assimilation rate were assessed on an area (Aarea) and mass (Amass) basis. S. ferrugineus exhibited greater root and lower shoot length in comparison to S. pohlii. The high shoot growth and concomitantly substantial root length of S. camporum may illustrate why this species is widely distributed in the cerrado sensu lato areas, whereas the deep roots of S. ferrugineus could account for its occurrence in the cerrado s. str. In the field, an irradiance-diminishing gradient enlarged the SLA of S. pohlii, which positively influenced its Amass, and which could partially explain its occurrence in shady habitats. However, a non-plastic trait, such as the high shoot length of S. pohlii, is more likely to be responsible for the success of this species in forest habitats.

scholarly journals Effect of nitrogen addition on the comparative productivity of corn and velvetleaf (Abutilon theophrasti)

Weed Science ◽  
2006 ◽  
Vol 54 (02) ◽  
pp. 354-363 ◽  
Author(s):  
Darren C. Barker ◽  
Stevan Z. Knezevic ◽  
Alex R. Martin ◽  
Daniel T. Walters ◽  
John L. Lindquist
Keyword(s):  
Leaf Area ◽  
Field Experiments ◽  
Yield Loss ◽  
Biomass Accumulation ◽  
Nitrogen Addition ◽  
Corn Yield ◽  
N Addition ◽  
Area Index ◽  
Nitrogen Levels ◽  
Weed Growth

Weeds that respond more to nitrogen fertilizer than crops may be more competitive under high nitrogen (N) conditions. Therefore, understanding the effects of nitrogen on crop and weed growth and competition is critical. Field experiments were conducted at two locations in 1999 and 2000 to determine the influence of varying levels of N addition on corn and velvetleaf height, leaf area, biomass accumulation, and yield. Nitrogen addition increased corn and velvetleaf height by a maximum of 15 and 68%, respectively. N addition increased corn and velvetleaf maximum leaf area index (LAI) by up to 51 and 90%. Corn and velvetleaf maximum biomass increased by up to 68 and 89% with N addition. Competition from corn had the greatest effect on velvetleaf growth, reducing its biomass by up to 90% compared with monoculture velvetleaf. Corn response to N addition was less than that of velvetleaf, indicating that velvetleaf may be most competitive at high levels of nitrogen and least competitive when nitrogen levels are low. Corn yield declined with increasing velvetleaf interference at all levels of N addition. However, corn yield loss due to velvetleaf interference was similar across N treatments except in one site–year, where yield loss increased with increasing N addition. Corn yield loss due to velvetleaf interference may increase with increasing N supply when velvetleaf emergence and early season growth are similar to that of corn.

Echinochloa crus-galli (barnyard grass).

2021 ◽  
Author(s):  
Julissa Rojas-Sandoval ◽  
Pedro Acevedo-Rodríguez
Keyword(s):  
Soil Nitrogen ◽  
Crop Yields ◽  
Grass Species ◽  
Coastal Forests ◽  
Virus Diseases ◽  
Forage Crops ◽  
Barnyard Grass ◽  
Natural Grasslands ◽  
The World ◽  
Environmental Weed

Abstract E. crus-galli is a grass species included in the Global Compendium of Weeds (Randall, 2012) and which is considered one of the world's worst weeds. This species has the capability to reduce crop yields and cause forage crops to fail by removing up to 80% of the available soil nitrogen. E. crus-galli is considered the world's worst weed in rice paddies and has been also listed as a weed in at least other 36 crops throughout tropical and temperate regions of the world (Holm et al., 1991). The high levels of nitrates it accumulates can poison livestock. It also acts as a host for several mosaic virus diseases. E. crus-galli is also considered an environmental weed that has become invasive in natural grasslands, coastal forests and disturbed sites in Asia, Africa, Australia, Europe and America (FAO, 2014; USDA-ARS, 2014).

Carbon Dioxide Assimilation by Pineapple Plants, Ananas comosus (L.) Merr. I. Effects of Daily Irradiance

1980 ◽  
Vol 7 (4) ◽  
pp. 363 ◽  
Author(s):  
PJM Sale ◽  
TF Neales
Keyword(s):  
Leaf Area ◽  
Leaf Tissue ◽  
Extended Period ◽  
Titratable Acidity ◽  
Dry Weight ◽  
Co2 Assimilation ◽  
Co2 Exchange ◽  
Ananas Comosus ◽  
Molar Ratio ◽  
Weight Changes

Net carbon exchange over 24-h cycles was measured in well watered pineapple plants, using a 'minicrop' in field assimilation chambers and single leaves in a growth cabinet. Whole plants under natural light and a standard 30°C day/15°C night regime showed crassulacean acid metabolism, nearly all assimilation occurring in the dark period, with a net efflux of CO2 in the day. Assimilation, as measured by both CO2 exchange and changes in titratable acidity in the leaf tissue, was markedly dependent on the total photosynthetically active radiation incident in the previous photoperiod. The molar ratio of the maximum acidity change to maximum net nocturnal CO2 influx was 1.8 : 1. The rate of deacidification depended on the irradiance in the current photoperiod. Efflux in the photoperiod was largely independent of irradiance, but was greater at very low irradiances. Maximum rates of CO2 assimilation in the minicrop were about 15 ng cm-2 (leaf area) s-1 in the dark at the standard temperature regime, and 22 ng-2 s-1 when photoperiod assimilation was induced by a 20°C day/30°C night regime. Similar rates were recorded in the single-leaf experiments, and are higher than those previously found for pineapple. Over a 24-h period, mean rates of about 6 ng cm-2 (leaf area) s-1 were recorded, in good agreement with measured dry weight changes over an extended period. These data help to explain earlier discrepancies in the literature between measured rates of CO2 assimilation and of crop growth rates in pineapples.

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