scholarly journals Facilitation Effects of Haloxylon salicornicum Shrubs on Associated Understory Annuals, and a Modified “Stress-Gradient” Hypothesis for Droughty Times

Plants ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1726
Author(s):  
Nasr H. Gomaa ◽  
Ahmad K. Hegazy ◽  
Arafat Abdel Hamed Abdel Latef
Keyword(s):  
Species Richness ◽  
Water Availability ◽  
Stress Gradient ◽  
Growing Season ◽  
Annual Species ◽  
Negative Effects ◽  
Growing Seasons ◽  
Dry Seasons ◽  
The Impact ◽  
Haloxylon Salicornicum

Perennial shrub-annual plant interactions play key roles in desert regions influencing the structure and dynamics of plant communities there. In the present study, carried out in northwestern Saudi Arabia, we examined the effect of Haloxylon salicornicum shrubs on their associated understory annual species across four consecutive growing seasons, along with a record of the seasonal rainfall patterns. We measured density and species richness of all the annual species in permanent quadrats located beneath individual shrubs, as well as in the spaces between shrubs. During wet growing season H. salicornicum shrubs significantly enhanced the density and species richness of sub-canopy species, whereas in the relatively dry seasons they exerted negative effects on the associated species. In all growing seasons, the presence of shrubs was associated with enhanced soil properties, including increased organic carbon content, silt + clay, and levels of nutrients (N, P and K). Shrubs improved soil moisture content beneath their canopies in the wet growing season, while in the dry seasons they had negative effects on water availability. Differences in effects of H. salicornicum on understory plants between growing seasons seem due to the temporal changes in the impact of shrubs on water availability. Our results suggest the facilitative effects of shrubs on sub-canopy annuals in arid ecosystems may switch to negative effects with increasing drought stress. We discuss the study in light of recent refinements of the well-known “stress-gradient hypothesis”.

Assessing the impact of seasonal precipitation and temperature on vegetation in a grass-dominated rangeland

2014 ◽  
Vol 36 (2) ◽  
pp. 185 ◽  
Author(s):  
Fang Chen ◽  
Keith T. Weber
Keyword(s):  
Vegetation Index ◽  
Climatic Factors ◽  
Growing Season ◽  
Vegetation Growth ◽  
Factors Affecting ◽  
Growing Seasons ◽  
Normalised Difference Vegetation Index ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
The Impact ◽  
Precipitation And Temperature

Changes in vegetation are affected by many climatic factors and have been successfully monitored through satellite remote sensing over the past 20 years. In this study, the Normalised Difference Vegetation Index (NDVI), derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) onboard the Terra satellite, was selected as an indicator of change in vegetation. Monthly MODIS composite NDVI at a 1-km resolution was acquired throughout the 2004–09 growing seasons (i.e. April–September). Data describing daily precipitation and temperature, primary factors affecting vegetation growth in the semiarid rangelands of Idaho, were derived from the Surface Observation Gridding System and local weather station datasets. Inter-annual and seasonal fluctuations of precipitation and temperature were analysed and temporal relationships between monthly NDVI, precipitation and temperature were examined. Results indicated NDVI values observed in June and July were strongly correlated with accumulated precipitation (R2 >0.75), while NDVI values observed early in the growing season (May) as well as late in the growing season (August and September) were only moderately related with accumulated precipitation (R2 ≥0.45). The role of ambient temperature was also apparent, especially early in the growing season. Specifically, early growing-season temperatures appeared to significantly affect plant phenology and, consequently, correlations between NDVI and accumulated precipitation. It is concluded that precipitation during the growing season is a better predictor of NDVI than temperature but is interrelated with influences of temperature in parts of the growing season.

scholarly journals The onset in spring and the end in autumn of the thermal and vegetative growing season affect calving time and reproductive success in reindeer

2019 ◽  
Vol 66 (2) ◽  
pp. 123-134 ◽  
Author(s):  
Amélie Paoli ◽  
Robert B Weladji ◽  
Øystein Holand ◽  
Jouko Kumpula
Keyword(s):  
Reproductive Success ◽  
Time Lag ◽  
Growing Season ◽  
Plant Phenology ◽  
Negative Effects ◽  
Main Hypothesis ◽  
Vegetation Growth ◽  
Growing Seasons ◽  
Finnish Lapland ◽  
Reindeer Population

Abstract A developing trophic mismatch between the peak of energy demands by reproducing animals and the peak of forage availability has caused many species’ reproductive success to decrease. The match–mismatch hypothesis (MMH) is an appealing concept that can be used to assess such fitness consequences. However, concerns have been raised on applying the MMH on capital breeders such as reindeer because the reliance on maternal capita rather than dietary income may mitigate negative effects of changing phenologies. Using a long-term dataset of reindeer calving dates recorded since 1970 in a semidomesticated reindeer population in Finnish Lapland and proxies of plant phenology; we tested the main hypothesis that the time lag between calving date and the plant phenology in autumn when females store nutrient reserves to finance reproduction would lead to consequences on reproductive success, as the time lag with spring conditions would. As predicted, the reproductive success of females of the Kutuharju reindeer population was affected by both the onset of spring green-up and vegetative senescence in autumn as calves were born heavier and with a higher first-summer survival when the onset of the vegetation growth was earlier and the end of the thermal growing season the previous year was earlier as well. Our results demonstrated that longer plant growing seasons might be detrimental to reindeer’s reproductive success if a later end is accompanied by a reduced abundance of mushrooms.

scholarly journals Monitoring soil microorganisms with community-level physiological profiles using Biolog EcoPlates™ in Chaohu lakeside wetland, east China

2019 ◽  
Author(s):  
Zhen Teng ◽  
Wei Fan ◽  
Huiling Wang ◽  
Xiaoqing Cao ◽  
Xiaoniu Xu
Keyword(s):  
Microbial Communities ◽  
Carbon Sources ◽  
Growing Season ◽  
Wiener Index ◽  
Utilization Efficiency ◽  
Growth Trend ◽  
Biolog Ecoplates ◽  
Growing Seasons ◽  
Dormant Season ◽  
The Impact

AbstractUnder the circumstance of wetland degradation, we used Biolog EcoPlates™ method to investigate the impact of ecological restoration on the function of topsoil microbial communities by monitoring their metabolic diversity around Chaohu lakeside wetland. Four restoration patterns including reed shoaly land (RL), poplar plantation land (PL), abandoned shoaly grassland (GL) and cultivated flower land (FL) were selected. The result showed a rapid growth trend at the initial stage of incubation, following the fastest change rate at 72 h in both dormant and growing seasons, and the AWCD values of RL pattern was the highest at the detection points of each culture time, while the GL were the lowest. The calculation of diversity indicators also displayed significant lower McIntosh index in dormant season and Shannon-Wiener index in growing season in GL than in the others (P < 0.05). Carbohydrates and carboxylic acids were found to be the dominant substrates used in dormant season, whereas amino acids, polymers and phenolic acids were increasingly utilized by the microbial communities in growing season. We observed soil total potassium as the key factor that significantly affected the utilization efficiency of different carbon sources in both seasons (P < 0.05).

The Formation of Traumatic Rows of Resin Ducts in Larix Decidua and Picea Abies (Pinaceae) as a Result of Wounding Experiments in the Dormant Season

IAWA Journal ◽  
2009 ◽  
Vol 30 (2) ◽  
pp. 199-215 ◽  
Author(s):  
Holger Gärtner ◽  
Ingo Heinrich
Keyword(s):  
Picea Abies ◽  
Growing Season ◽  
Larix Decidua ◽  
Mass Movements ◽  
Resin Ducts ◽  
Growing Seasons ◽  
Dormant Season ◽  
Wound Reaction ◽  
The Impact ◽  
Geographical Locations

Wounding experiments, imitating the impact of geomorphic processes such as rock fall, were performed on Larix decidua Mill. and Picea abies (L.) Karst., before the beginning and at the end of the growing season. This was done to evaluate the timing and spread of traumatic rows of resin ducts (TDs) as a result of wounding during dormancy, when most mass movements occur. All treatments were successful in inducing TDs. However, a high inter- and intra-species variability concerning the timing and position of the TDs was noted. In larch, TDs were formed as first cells after wounding (immediate reaction) only in the vicinity of the wound. In contrast, none of the spruce trees exhibited immediate reactions. Neither larch nor spruce formed continuous TDs around the stem. TDs in larch were more extensive if, in addition, stems were bent before the growing season. In contrast, spruce showed this reaction when bent at the end of the growing season. The results indicate that the varying lengths of the growing seasons at different geographical locations need to be taken into account before an immediate wound reaction can be clearly defined, if an increase of the reliability and accuracy of process reconstructions is aimed for.

scholarly journals The impact of plant density on the seed yield and the spring field pea’s yield component

Poljoprivreda ◽  
2020 ◽  
Vol 26 (1) ◽  
pp. 25-31
Author(s):  
Goran Krizmanić ◽  
Tihomir Čupić ◽  
Snežana V. Jovanović ◽  
Monika Marković ◽  
Andrija Brkić ◽  
...  
Keyword(s):  
Plant Height ◽  
Seed Yield ◽  
Plant Density ◽  
Block Design ◽  
Growing Season ◽  
Yield Component ◽  
Field Pea ◽  
Growing Seasons ◽  
Plant Densities ◽  
The Impact

The spring field pea is one of the most important coarse legumes. This study was carried out to investigate the response of a spring field pea variety to three plant densities (50, 100, and 150 plant m-2) during the 2017 and 2019 growing seasons in eastern Croatia. The field study was set up as a Randomized Complete Block Design (RCBD) in four replications. The results have demonstrated a significant effect of the plant densities and the growing seasons on the seed yield and on the following yield components: plant height and the number of pods/plant. The effect of plant densities on the number of seeds/pod and the thousand-seed weight was not significant. As for a growing season, the highest seed yield, plant height, the number of pods/plant were obtained in the second growing season. Furthermore, a maximum seed yield was recorded at the 150-plant m-2 plant density. This study has demonstrated that planting the spring field pea at different plant densities significantly modifies the spring field pea yield, plant height and number of pods/plant.

scholarly journals Effects of Timing and Intensity of Summer Pruning on Vegetative Traits of Two Southern Highbush Blueberry Cultivars

HortScience ◽  
2015 ◽  
Vol 50 (1) ◽  
pp. 68-73 ◽  
Author(s):  
Alisson P. Kovaleski ◽  
Jeffrey G. Williamson ◽  
Bruno Casamali ◽  
Rebecca L. Darnell
Keyword(s):  
Vegetative Growth ◽  
Growing Season ◽  
Shoot Length ◽  
First Year ◽  
Highbush Blueberry ◽  
Negative Effects ◽  
The Third ◽  
Growing Seasons ◽  
Vegetative Traits ◽  
Southern Highbush

Pruning is a recommended practice for blueberry (Vaccinium spp.) production and is usually done in the summer in warm subtropical climates with long growing seasons. Summer pruning promotes healthy vegetative growth during the remainder of the growing season; however, research-based recommendations for summer pruning strategies are lacking. The objective of this study was to determine effects of summer pruning timing and intensity on vegetative growth in ‘Jewel’ and ‘Emerald’ southern highbush blueberry (V. corymbosum-interspecific hybrid), two cultivars of the primary species grown in subtropical areas. To determine effects of pruning time, 30% of the canopy was removed in June or July. To determine pruning intensity effects, either 30% or 60% of the canopy was removed in June, both followed by shoot tipping in July. Both timing and intensity treatments were compared with a non-pruned control. Lack of pruning in the first year had no negative effects on growth; however, lack of pruning for two or more seasons decreased regrowth volume and shoot length of both cultivars. By the third season, canopy regrowth volume in both cultivars decreased in the non-pruned control compared with the 30% and 60% pruning treatments and compared with the June pruning treatment. Disease infection in ‘Jewel’ was also increased in the non-pruned control compared with these pruning treatments. Summer pruning, regardless of timing or intensity, generally increased vigor of vegetative growth for both cultivars and decreased incidence of leaf disease in ‘Jewel’.

scholarly journals Sowing terms as a way to increase yield of soybean varieties with different vegetation period

1970 ◽  
pp. 71-81
Author(s):  
V.H. Moldovan ◽  
Zh.A. Moldovan ◽  
S.I. Sobchuk
Keyword(s):  
Seed Yield ◽  
Growth And Development ◽  
Weather Conditions ◽  
Growing Season ◽  
Vegetation Period ◽  
Growing Seasons ◽  
Sowing Dates ◽  
Individual Productivity ◽  
The Impact ◽  
Late Sowing

Purpose. To study of the influence of sowing terms on plant growth and development, formation of indicators of individual productivity and seed yield by soybean varieties with different vegetation period in conditions of the western Forest-Steppe of Ukraine. Methods. Field experiment, calculation and weight, mathematical statistics. Results. Weather conditions in the years of the research were characterized by high average daily temperatures against the background of uneven distribution of precipitation by phases of soybean development, which together with the studied factor had a significant impact on the growth and development of soybean plants and seed yield formation. It was found that the studied soybean varieties with different growing seasons react differently to growing conditions. The timing of sowing significantly affects the height of attachment of the lower bean, the number of beans per plant and seeds in the bean, the weight of 1000 seeds and the weight of seeds per 1 plant. However, they have almost no effect on the number of seeds in the bean. It was investigated that the soybean variety Diadema Podillya forms the highest yields at the optimal and late sowing dates, while the soybean of the KiVin, Knyazhna, Khutoryanochka and Triada varieties – at the late sowing period (second decade of May). The increase in seed yield compared to sowing in the optimal time (first decade of May) was 6.6%, 3.1%, 13.8% and 9.6%, respectively. Conclusions. Sowing terms in interaction with the weather conditions of the growing season, have a significant impact on the formation of indicators of individual productivity and seed yield of soybean varieties with different growing seasons. That is why in the conditions of climate change, uneven moisture supply during the growing season and the emergence of new varieties it is advisable to continue research to study the impact of sowing dates, in interaction with other factors, on the formation of individual productivity and yield of soybean seeds.

scholarly journals Narrowband Blue and Red LED Supplements Impact Key Flavor Volatiles in Hydroponically Grown Basil Across Growing Seasons

2021 ◽  
Vol 12 ◽  
Author(s):  
Hunter A. Hammock ◽  
Dean A. Kopsell ◽  
Carl E. Sams
Keyword(s):  
Growth Period ◽  
Growing Season ◽  
Gas Chromatography Mass Spectrometry ◽  
Greenhouse Production ◽  
Light Emitting ◽  
Growing Seasons ◽  
Red Led ◽  
Lighting Systems ◽  
Hydroponically Grown ◽  
The Impact

The use of light-emitting diodes (LEDs) in commercial greenhouse production is rapidly increasing because of technological advancements, increased spectral control, and improved energy efficiency. Research is needed to determine the value and efficacy of LEDs in comparison to traditional lighting systems. The objective of this study was to establish the impact of narrowband blue (B) and red (R) LED lighting ratios on flavor volatiles in hydroponic basil (Ocimum basilicum var. “Genovese”) in comparison to a non-supplemented natural light (NL) control and traditional high-pressure sodium (HPS) lighting. “Genovese” basil was chosen because of its high market value and demand among professional chefs. Emphasis was placed on investigating concentrations of important flavor volatiles in response to specific ratios of narrowband B/R LED supplemental lighting (SL) and growing season. A total of eight treatments were used: one non-supplemented NL control, one HPS treatment, and six LED treatments (peaked at 447 nm/627 nm, ±20 nm) with progressive B/R ratios (10B/90R, 20B/80R, 30B/70R, 40B/60R, 50B/50R, and 60B/40R). Each SL treatment provided 8.64 mol ⋅ m−2 ⋅ d–1 (100 μmol ⋅ m–2 ⋅ s–1, 24 h ⋅ d–1). The daily light integral (DLI) of the NL control averaged 9.5 mol ⋅ m−2 ⋅ d–1 during the growth period (ranging from 4 to 18 mol ⋅ m−2 ⋅ d–1). Relative humidity averaged 50%, with day/night temperatures averaging 27.4°C/21.8°C, respectively. Basil plants were harvested 45 days after seeding, and volatile organic compound profiles were obtained by gas chromatography–mass spectrometry. Total terpenoid concentrations were dramatically increased during winter months under LED treatments, but still showed significant impacts during seasons with sufficient DLI and spectral quality. Many key flavor volatile concentrations varied significantly among lighting treatments and growing season. However, the concentrations of some compounds, such as methyl eugenol, were three to four times higher in the control and decreased significantly for basil grown under SL treatments. Maximum concentrations for each compound varied among lighting treatments, but most monoterpenes and diterpenes evaluated were highest under 20B/80R to 50B/50R. This study shows that supplemental narrowband light treatments from LED sources may be used to manipulate secondary metabolic resource allocation. The application of narrowband LED SL has great potential for improving overall flavor quality of basil and other high-value specialty herbs.

The More Control, the Better?

2014 ◽  
Vol 26 (2) ◽  
pp. 81-91 ◽  
Author(s):  
Jeeyun Oh ◽  
Mun-Young Chung ◽  
Sangyong Han
Keyword(s):  
Mixed Design ◽  
Negative Effects ◽  
Story Structure ◽  
Content Type ◽  
High User ◽  
User Control ◽  
Rigorous Research ◽  
Control Versus ◽  
The Media ◽  
The Impact

Despite of the popularity of interactive movie trailers, rigorous research on one of the most apparent features of these interfaces – the level of user control – has been scarce. This study explored the effects of user control on users’ immersion and enjoyment of the movie trailers, moderated by the content type. We conducted a 2 (high user control versus low user control) × 2 (drama film trailer versus documentary film trailer) mixed-design factorial experiment. The results showed that the level of user control over movie trailer interfaces decreased users’ immersion when the trailer had an element of traditional story structure, such as a drama film trailer. Participants in the high user control condition answered that they were less fascinated with, absorbed in, focused on, mentally involved with, and emotionally affected by the movie trailer than participants in the low user control condition only with the drama movie trailer. The negative effects of user control on the level of immersion for the drama trailer translated into users’ enjoyment. The impact of user control over interfaces on immersion and enjoyment varies depending on the nature of the media content, which suggests a possible trade-off between the level of user control and entertainment outcomes.

Monetary policy and the effect of the transfer of oil prices to inflation

2020 ◽  
pp. 41-50
Author(s):  
Ph. S. Kartaev ◽  
I. D. Medvedev
Keyword(s):  
Monetary Policy ◽  
Inflation Targeting ◽  
Dynamic Models ◽  
Oil Prices ◽  
Oil Price ◽  
Oil Price Shocks ◽  
Negative Effects ◽  
Price Shocks ◽  
Policy Regime ◽  
The Impact

The paper examines the impact of oil price shocks on inflation, as well as the impact of the choice of the monetary policy regime on the strength of this influence. We used dynamic models on panel data for the countries of the world for the period from 2000 to 2017. It is shown that mainly the impact of changes in oil prices on inflation is carried out through the channel of exchange rate. The paper demonstrates the influence of the transition to inflation targeting on the nature of the relationship between oil price shocks and inflation. This effect is asymmetrical: during periods of rising oil prices, inflation targeting reduces the effect of the transfer of oil prices, limiting negative effects of shock. During periods of decline in oil prices, this monetary policy regime, in contrast, contributes to a stronger transfer, helping to reduce inflation.

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