scholarly journals Plant population and soil origin effects on rhizosphere nematode community composition of a range-expanding plant species and a native congener

Oecologia ◽  
2020 ◽  
Vol 194 (1-2) ◽  
pp. 237-250
Author(s):  
Rutger A. Wilschut ◽  
Kim J. H. Magnée ◽  
S. Geisen ◽  
W. H. van der Putten ◽  
O. Kostenko
Keyword(s):  
Plant Species ◽  
Plant Population ◽  
Enemy Release ◽  
Native Range ◽  
Centaurea Stoebe ◽  
Plant Populations ◽  
Range Theory ◽  
Dispersal Abilities ◽  
Population Effects ◽  
Root Feeding

Abstract Climate change causes species range expansions to higher latitudes and altitudes. It is expected that, due to differences in dispersal abilities between plants and soil biota, range-expanding plant species will become associated with a partly new belowground community in their expanded range. Theory on biological invasions predicts that outside their native range, range-expanding plant species may be released from specialist natural enemies, leading to the evolution of enhanced defence against generalist enemies. Here we tested the hypothesis that expanded range populations of the range-expanding plant species Centaurea stoebe accumulate fewer root-feeding nematodes than populations from the original range. Moreover, we examined whether Centaurea stoebe accumulates fewer root-feeding nematodes in expanded range soil than in original range soil. We grew plants from three expanded range and three original range populations of C. stoebe in soil from the original and from the new range. We compared nematode communities of C. stoebe with those of C. jacea, a congeneric species native to both ranges. Our results show that expanded range populations of C. stoebe did not accumulate fewer root-feeding nematodes than populations from the original range, but that C. stoebe, unlike C. jacea, accumulated fewest root-feeding nematodes in expanded range soil. Moreover, when we examined other nematode feeding groups, we found intra-specific plant population effects on all these groups. We conclude that range-expanding plant populations from the expanded range were not better defended against root-feeding nematodes than populations from the original range, but that C. stoebe might experience partial belowground enemy release.

scholarly journals PLANT SPACING AND NITROGEN INFLUENCE ON STRAWBERRY GROWTH AND FRUITING

HortScience ◽  
1990 ◽  
Vol 25 (4) ◽  
pp. 399c-399
Author(s):  
Elden J. Stang ◽  
Gavin G. Weis
Keyword(s):  
Plant Population ◽  
Fruit Yield ◽  
Growth And Yield ◽  
Higher Plant ◽  
Plant Populations ◽  
Available N ◽  
Berry Size ◽  
Plant Densities ◽  
Nitrogen Treatments ◽  
Population Effects

`Raritan' and `Guardian' strawberry were grown in the matted row system with controlled plant densities of 1, 2, 3, 4 or 5 plants/0.09m2 for comparison to a non-thinned matted row averaging 9 plants/0.09m2. Nitrogen treatments were superimposed on plant spacings at 3 week intervals in preharvest and postharvest applications. Total seasonal available N was 0, 36, 54 and 76 kg/ha. Fruit yield per plant decreased as plant population increased. Berry size declined with increased plant population but number of fruit per plant was not influenced. For both cultivars, plant populations of 4 to 5 plants/0.09m2 resulted in maximum fruit yield. Number of branch crowns for all treatments was 2.5-3.5/plant in the second growing season. Branch crown numbers were reduced with higher plant populations. N effects were independent of plant population effects and did not compensate for lower yields at low plant populations in more or larger berries. Optimum water management may be more important than N fertilizer in determing strawberry plant growth and yield.

Effects of Plant Population on Sole-crop Cassava in Sierra Leone

1978 ◽  
Vol 14 (3) ◽  
pp. 239-244 ◽  
Author(s):  
W. Godfrey-Sam-Aggrey
Keyword(s):  
Sierra Leone ◽  
Yield Components ◽  
Dry Matter ◽  
Weight Ratio ◽  
Land Plant ◽  
Plant Population ◽  
Root Weight ◽  
Plant Populations ◽  
Sole Crop ◽  
Yield And Yield Components

SUMMARYEffects of plant population on mean yield and yield components of 2-year sole cassava crops were studied on Njala upland soils of Sierra Leone in two experiments. Increasing plant population of multi-shoot Cocoa cassava over 7000/ha decreased all the parameters studied except top/root weight ratio, which increased. The observed effects were attributed to competition for environmental resources, since area of land/plant unit decreased as plant population increased. The relations between plant populations and yields of fresh root and cortex dry matter were asymptotic, indicating that the respective yields were products of the vegetative phase of cropping.

scholarly journals Landscape and Climate Influence the Patterns of Genetic Diversity and Inbreeding in Cerrado Plant Species

Diversity ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 421
Author(s):  
Luciana Cristina Vitorino ◽  
Mateus Neri Oliveira Reis ◽  
Layara Alexandre Bessa ◽  
Ueric José Borges de Souza ◽  
Fabiano Guimarães Silva
Keyword(s):  
Genetic Diversity ◽  
Plant Species ◽  
Environmental Conditions ◽  
Urban Areas ◽  
Isolation By Distance ◽  
Buffer Size ◽  
Mean Annual Temperature ◽  
Plant Populations ◽  
Landscape Features ◽  
Center Periphery

The anthropization of the landscape of the Cerrado biome that has occurred over the past few decades has fragmented its natural environments, impacting the connectivity of the plant populations and altering their gene flow. Plant species may also reduce population size in response to sub-optimal climatic and environmental conditions, and observed distribution patterns may align with theoretical schemes, such as the center–periphery model, that is, it is possible that populations on the edge have lower genetic diversity than center populations, theoretically submitted to environmental conditions closer to the optimum. In this context, we evaluate whether the genetic diversity and inbreeding coefficients of Cerrado plant species are affected by landscape features and climate characteristics, and in particular, if the distribution of the genetic diversity of these plants is consistent with the center–periphery model. To do this, we conducted a literature search for genetic studies of Cerrado plant populations using Scopus, Web of Science, and Scielo databases and the species found were used as a proxy to explore patterns throughout the biome. The data were analyzed using generalized linear mixed models (GLMM) and multiple matrix regressions (MMRRs) to evaluate the effects of landscape features and climatic variables on the observed (HO) and expected heterozygosity (HE), allelic richness (AR) and inbreeding (Fis) patterns of the local populations. The landscape was evaluated in terms of the percentage land cover of agriculture (AG), forestry (FO), remnant vegetation (RV), urban areas (UA), pasture (PA), and water (WA) within buffers of 1 km, 3 km, and 5 km around the study populations. We analyzed 121 populations of 31 plant species. The GLMMs showed that HO was affected by FO regardless of buffer size, while HE was also affected by FO, but also by WA and UA. AR was affected by WA and UA in all three buffer zones while the Fis was affected by FO and AU. The MMRRs showed that WA may affect HO, HE, and Fis within the 1 km buffer, while FO affects HO and UA affects AR within the 5 km buffer. In the case of the 1 km and 3 km buffers, however, the geographic distance between populations was identified as a factor determining the genetic diversity and inbreeding indices, indicating that isolation by distance may be an important factor defining the breeding patterns of the Cerrado plant populations. The GLMMs and MMRRs also showed that the mean annual temperature (MAT) and, to a lesser extent, isothermality (ISO) can explain the variation in genetic diversity observed in the Cerrado plant populations. We also found that the center–periphery model fits the distribution pattern observed in most of the species evaluated, including Annona crassiflora,Annona coriacea, Copaifera langsdorffii, and Eugenia dysenterica. Our results indicate that changes in the climate and the landscape of Brazilian Cerrado must be considered carefully to guarantee minimizing the impacts of these processes on the genetic diversity of Cerrado plant species and ensuring the long-term conservation of these species in this biome.

The influence of inter-row spacing and plant population on the yield of peanuts at Katherine, N.T

1962 ◽  
Vol 2 (4) ◽  
pp. 54 ◽  
Author(s):  
LJ Phillips ◽  
MJT Norman
Keyword(s):  
Plant Population ◽  
Row Spacing ◽  
Clay Loam ◽  
Plant Populations ◽  
Kernel Yield ◽  
Multifactorial Experiment

In 1957-58 and 1958-59, Virginia Bunch and Natal Common peanuts were sown on Tippers clay loam at Katherine, N.T., in a multifactorial experiment at two inter-row spacings (2 ft and 3 ft), four plant populations (10, 20, 40 and 80 thousand per acre) and two dates. In 1960-61, Natal Common only was sown at the same inter-row spacings, at two dates, and at populations of 10, 20, 30 and 40 thousand per acre. Over two seasons, the yield of Virginia Bunch kernels was not significantly influenced by variation in population, though the yield of hay was 42 per cent higher at 80,000 plants per acre than at 10,000 plants per acre. Kernel yields from 2 f t rows were 14 per cent higher than from 3 f t rows. In the first two seasons, the yield of Natal Common kernels was lower at 80,000 plants per acre than at 40,000 plants per acre. Over three seasons, maximum kernel and h g yields were achieved at 40,000 plants per acre ; the kernel yield at this population was 35 per cent greater than at 10,000 plants per acre. With early-planted Natal Common, 2.ft rows gave an 11 per cent higher yield of kernels than 3 f t rows, but with later planting there was no significant effect of inter-row spacing. The optimum economic seeding rates were estimated approximately as 30 lb an acre for Virginia Bunch and 45 lb an acre for Natal Common.

Effects of Sheep Grazing Astrebla Grasslands in Central Western Queensland. Iii. Dynamics of Astrebla Spp. Under Grazing and Exclosure Between 1975 and 1986.

1991 ◽  
Vol 13 (1) ◽  
pp. 36 ◽  
Author(s):  
DM Orr ◽  
CJ Evenson
Keyword(s):  
Population Dynamics ◽  
Seed Production ◽  
Basal Area ◽  
Summer Rainfall ◽  
High Variability ◽  
Plant Population ◽  
Sheep Grazing ◽  
Plant Population Dynamics ◽  
Winter Rainfall ◽  
Plant Populations

The basal area, yield and plant populations of Astrebla spp. were monitored under grazing and exclosure in Astrebla grasslands between 1975 and 1986. This study was undertaken to develop an understanding of how Astrebla spp. respond to grazing, particularly in relation to the high variability of rainfall. Basal area and yield of Astrebla spp. varied widely between years in response to summer rainfall, with few differences between exclosure and grazing. The failure of summer rainfall resulted in increased utilization of Astrebla spp. but this effect was partially offset in some years by the growth of forb species following winter rainfall. Grazing stimulated the recruitment of Astrebla spp. seedlings by increasing the density of inflorescences which, in turn, increased seed production. Survival of seedling cohorts depended on adequate summer rainfall and grazing tended to enhance cohort survival. There was a greater plant flux under grazing than under exclosure. It was concluded that rainfall is the major factor influencing the biomass and plant population dynamics of Astrebla spp. and that grazing up to about 30% utilization is not detrimental to Astrebla spp.

Row Spacing and Plant Population Effects on Yield Components of Soybean

1989 ◽  
Vol 81 (6) ◽  
pp. 947-951 ◽  
Author(s):  
W. J. Ethredge ◽  
D. A. Ashley ◽  
J. M. Woodruff
Keyword(s):  
Yield Components ◽  
Plant Population ◽  
Row Spacing ◽  
Population Effects

scholarly journals The influence of warming and biotic interactions on the potential for range expansion of native and nonnative species

AoB Plants ◽  
2020 ◽  
Vol 12 (5) ◽  
Author(s):  
Betsy von Holle ◽  
Sören E Weber ◽  
David M Nickerson
Keyword(s):  
Plant Species ◽  
Range Expansion ◽  
Species Interactions ◽  
Native Species ◽  
Invasive Plant ◽  
Soil Microbes ◽  
Enemy Release ◽  
Native Plant ◽  
Soil Pathogens ◽  
Microbe Interactions

Abstract Plant species ranges are expected to shift in response to climate change, however, it is unclear how species interactions will affect range shifts. Because of the potential for enemy release of invasive nonnative plant species from species-specific soil pathogens, invasive plants may be able to shift ranges more readily than native plant species. Additionally, changing climatic conditions may alter soil microbial functioning, affecting plant–microbe interactions. We evaluated the effects of site, plant–soil microbe interactions, altered climate, and their interactions on the growth and germination of three congeneric shrub species, two native to southern and central Florida (Eugenia foetida and E. axillaris), and one nonnative invasive from south America (E. uniflora). We measured germination and biomass for these plant species in growth chambers grown under live and sterile soils from two sites within their current range, and one site in their expected range, simulating current (2010) and predicted future (2050) spring growing season temperatures in the new range. Soil microbes (microscopic bacteria, fungi, viruses and other organisms) had a net negative effect on the invasive plant, E. uniflora, across all sites and temperature treatments. This negative response to soil microbes suggests that E. uniflora’s invasive success and potential for range expansion are due to other contributing factors, e.g. higher germination and growth relative to native Eugenia. The effect of soil microbes on the native species depended on the geographic provenance of the microbes, and this may influence range expansion of these native species.

scholarly journals Plant Population Affects Yield and Fruit Size of Pumpkin

HortScience ◽  
1999 ◽  
Vol 34 (6) ◽  
pp. 1076-1078 ◽  
Author(s):  
Stephen Reiners ◽  
Dale I.M. Riggs
Keyword(s):  
Growth Habit ◽  
Plant Competition ◽  
Fruit Size ◽  
Field Studies ◽  
Plant Population ◽  
Lower Yield ◽  
Marketable Yield ◽  
Plant Populations ◽  
Fruit Number ◽  
Row Width

Field studies were conducted in 1996 on two pumpkin (Cucurbita pepo L.) cultivars, `Howden' (vining-type growth habit) and `Wizard' (semi-bush growth habit), at two locations to determine the effect of plant population and row width on marketable yield. Increasing plant populations from 2990 to 8960 plants per hectare resulted in significantly greater fruit number and yield at both locations and for both varieties. Average fruit size declined at the highest populations. Increasing row width from 1.8 to 3.6 m resulted in a slight but significant decrease in number of fruit per hectare with no effect on other yield parameters. At one location, the effect of row width on yield and number of fruit per hectare depended on the population. At low populations, row width did not influence yield or fruit number; at high populations, wide rows produced lower yield and fewer fruit than narrow rows. The results demonstrate that growers may increase pumpkin yield by increasing plant populations but should use narrower row widths and wider in-row spacing. Growers who choose higher populations should ensure that all inputs are optimized to reduce potential plant-to-plant competition and use regionally adapted cultivars.

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