Cooler temperatures favour growth of wild leek (Allium tricoccum), a deciduous forest spring ephemeral

Botany ◽  
2012 ◽  
Vol 90 (11) ◽  
pp. 1125-1132 ◽  
Author(s):  
Antoine Bernatchez ◽  
Line Lapointe
Keyword(s):  
Temperature Regime ◽  
Deciduous Forest ◽  
Plant Biomass ◽  
Photochemical Efficiency ◽  
Early Spring ◽  
Photochemical Quenching ◽  
Spring Ephemerals ◽  
Spring Ephemeral ◽  
Short Period ◽  
Allium Tricoccum

Allium tricoccum Aiton is a common spring ephemeral of hardwood deciduous forests of northeastern North America. It takes advantage of the short period of high light conditions between snowmelt and canopy closure to complete its vegetative life cycle and accumulate carbohydrate reserves for the following year. Previous studies on other spring ephemerals have shown that growth of these species is enhanced when grown at low temperature, typical of very early spring. We thus quantified the effect of three growth temperature regimes, i.e., 18 °C day – 14 °C night, 12 °C day – 8 °C night, and 8 °C day – 6 °C night, which have previously been tested on Erythronium americanum, another spring ephemeral. Gas exchange, chlorophyll a fluorescence, and plant biomass were measured repeatedly throughout the growth season. Growth was greatest under the 12 °C day – 8 °C night temperature regime, consistent with enhanced net photosynthetic rates (Pn), photochemical quenching (qP), and photochemical efficiency of photosynthesis (ΦPSII) at this temperature regime throughout the season. Pn was similar at 18 °C day – 14 °C night and 8 °C day – 6 °C night, but leaves had a greater duration at 8 °C day – 6 °C night; however, bulb biomass was not greater at 8 °C day – 6 °C night than at 18 °C day – 14 °C night. This study corroborates the general sensitivity of spring ephemerals to warmer temperatures. It also highlights species differences that might be caused by their specific carbon metabolism at the bulb level.

scholarly journals Late canopy closure delays senescence and promotes growth of the spring ephemeral wild leek (Allium tricoccum)

Botany ◽  
2017 ◽  
Vol 95 (5) ◽  
pp. 457-467 ◽  
Author(s):  
Pierre-Paul Dion ◽  
Julie Bussières ◽  
Line Lapointe
Keyword(s):  
Light Availability ◽  
Growing Season ◽  
Tree Canopy ◽  
Strong Impact ◽  
Bud Burst ◽  
Growth And Survival ◽  
Spring Ephemerals ◽  
Spring Ephemeral ◽  
Tree Leaf ◽  
Allium Tricoccum

Spring ephemerals take advantage of the high light conditions in spring to accumulate carbon reserves through photosynthesis before tree leaves unfold. Recent work has reported delayed leaf senescence under constant light availability in some spring ephemerals, such as wild leek (Allium tricoccum). This paper aims to establish whether tree canopy composition and phenology can influence the growth of spring ephemerals through changes in their phenology. Wild leek bulbs were planted in 31 plots in southern Quebec, Canada, under canopies varying in composition and densities. Light availability and tree phenology were measured, along with other environmental conditions, and their effect on the growth of wild leeks was assessed with a redundancy analysis. Higher light availability resulted in better growth of wild leeks. The plants postponed their senescence under trees with late bud-burst, and thus better bulb growth and seed production were achieved. The tree litter and temperature and moisture levels of the soil also influenced the growth and survival of wild leeks. Thus, tree leaf phenology appears to have a strong impact on the growth of spring ephemerals by modulating the length of their growing season and their photosynthetic capacity. This underlines the importance of considering the variation of light availability throughout the growing season in the study of spring ephemerals.

Physiological and morphological responses to shade and nutrient additions of Claytonia virginica (Portulacaceae): implications for the "vernal dam" hypothesis

1998 ◽  
Vol 76 (8) ◽  
pp. 1340-1349 ◽  
Author(s):  
Wendy B Anderson ◽  
William G Eickmeier
Keyword(s):  
Nutrient Cycling ◽  
Field Experiments ◽  
Deciduous Forest ◽  
Nutrient Addition ◽  
Bisphosphate Carboxylase ◽  
Spring Ephemerals ◽  
Nutrient Additions ◽  
Spring Ephemeral ◽  
Morphological Responses ◽  
Claytonia Virginica

Because of their unique phenology and physiology, spring ephemeral herbs are believed to play an important role in intrasystem nutrient cycling in deciduous forest ecosystems. It was hypothesized that they function as a "vernal dam" by temporarily sequestering nutrients and preventing leaching from the system during a period of high nutrient availability. However, spring ephemerals require high-irradiance growing conditions. How do their physiological and morphological responses to ambient light and shade limit their ability to sequester excess nutrients? We performed field experiments using Claytonia virginica L. as a model to test several responses to shade and increasing levels of nutrient additions. We also examined the biomass responses and nutrient storage capacities of other spring ephemeral herbs. In C. virginica, shading reduced ribulose 1,5-bisphosphate carboxylase-oxygenase (Rubisco) activity, photosynthesis rate, specific leaf weight, leaf width/length (W/L), and biomass; nutrient additions increased W/L and biomass only under unshaded conditions. Other herbs responded similarly but reached maximum biomass at lower nutrient addition levels than C. virginica. Shading reduced and nutrient additions increased nitrogen and phosphorus concentrations in both C. virginica and other herbs. Shaded herbs generally reached nutrient saturation at lower nutrient addition levels than unshaded herbs. Overall, unshaded plants sequestered larger amounts of nutrients than shaded plants. This pattern is best explained by a reduction in biomass under shaded conditions. We concluded that C. virginica and other spring herbs, although important components in forest nutrient cycling in the early spring, are limited in their capacity to store excess nutrients, particularly when shaded.Key words: Claytonia virginica, nutrient cycling, spring ephemerals, vernal dam.

scholarly journals Effect of Daily Light Integral on Cucumber Plug Seedlings in Artificial Light Plant Factory

Horticulturae ◽  
2021 ◽  
Vol 7 (6) ◽  
pp. 139
Author(s):  
Jiawei Cui ◽  
Shiwei Song ◽  
Jizhu Yu ◽  
Houcheng Liu
Keyword(s):  
Dry Matter ◽  
Plant Biomass ◽  
Photochemical Efficiency ◽  
Early Spring ◽  
Production Costs ◽  
Shoot Biomass ◽  
Artificial Light ◽  
Cucumber Seedlings ◽  
Plant Factory ◽  
Speed Up

In a controlled environment, in an artificial light plant factory during early spring or midsummer, vegetable seedlings can be uniform, compact, and high quality. Appropriate light parameters can speed up the growth of seedlings and save on production costs. Two experiments were carried out in this study: (1) cucumber seedling growth under different daily light integrals (DLIs) (5.41–11.26 mol·m−2·d−1) and optimum DLI for seedling production were explored (experiment 1: Exp. 1); (2) under the same DLI selected by Exp. 1, the effects of different light intensities and photoperiods on cucumber seedlings were investigated (experiment 2: Exp. 2). The root biomass, root-to-shoot ratio, seedling index, and shoot dry matter rate increased as the DLI increased from 5.41 to 11.26 mol·m−2·d−1, while the shoot biomass and leaf area decreased in Exp. 1. The cucumber seedlings became more compact as DLI increased, but more flowers developed after transplanting when the DLI was 6.35 mol·m−2·d−1. Under the optimal DLI (6.35 mol·m−2·d−1), the optimal intensity was 110–125 μmol·m−2·s−1, and the optimal photoperiod was 14–16 h, in which plant biomass, shoot dry matter rate, seedling index, and photochemical efficiency were higher.

scholarly journals Pollination biology of the urban populations of an ancient forest, spring ephemeral plant

2016 ◽  
Vol 85 (2) ◽  
Author(s):  
Maciej A. Ziemiański ◽  
Marcin Zych
Keyword(s):  
Habitat Fragmentation ◽  
Pollen Limitation ◽  
Early Spring ◽  
Climatic Conditions ◽  
Urban Populations ◽  
Social Bees ◽  
Spring Ephemerals ◽  
Spring Ephemeral ◽  
Ephemeral Plant ◽  
Ancient Forest

Habitat fragmentation, caused by, among all, agriculture and urbanization, is one of the most important drivers of plant biodiversity decline worldwide. One of the signs of deteriorating zoogamous plant reproduction is pollen limitation, often associated with a decline in pollinator diversity and abundance. Various authors predict that the most vulnerable taxa are outbreeding plant species characterized by specialist pollination systems. We have, therefore, focused on self-incompatible <em>Corydalis solida</em>, an ancient forest, spring ephemeral plant, growing in three remnant urban populations in the city of Warsaw (Poland). Over two years, we checked for pollen limitation and recorded insect diversity and abundance for <em>C. solida</em> flowers. Our study populations composed of self-incompatible individuals were mainly visited by generalist pollinators, and produced more seeds when supplementally pollinated. Pollen limitation, however, was greater during 1 year with an early spring onset, when we observed a decline in floral visitors diversity and activity. This was probably an effect of phenological mismatch between plants and their pollinators, in this case, mostly social bees, i.e., over-wintered bumblebee queens and <em>Apis mellifera</em>. We conclude that for outbreeding zoogamous spring ephemerals, such as <em>C. solida</em> serviced by generalist pollinators, changing climatic conditions may override the effects of habitat fragmentation and influence their reproductive success.

scholarly journals Fire, land cover, and temperature drivers of bat activity in winter

Fire Ecology ◽  
2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Marcelo H. Jorge ◽  
Sara E. Sweeten ◽  
Michael C. True ◽  
Samuel R. Freeze ◽  
Michael J. Cherry ◽  
...  
Keyword(s):  
Land Cover ◽  
Habitat Management ◽  
Deciduous Forest ◽  
Pinus Palustris ◽  
Growing Season ◽  
Early Spring ◽  
Bat Activity ◽  
White Nose Syndrome ◽  
Dormant Season ◽  
Wind Energy Development

Abstract Background Understanding the effects of disturbance events, land cover, and weather on wildlife activity is fundamental to wildlife management. Currently, in North America, bats are of high conservation concern due to white-nose syndrome and wind-energy development impact, but the role of fire as a potential additional stressor has received less focus. Although limited, the vast majority of research on bats and fire in the southeastern United States has been conducted during the growing season, thereby creating data gaps for bats in the region relative to overwintering conditions, particularly for non-hibernating species. The longleaf pine (Pinus palustris Mill.) ecosystem is an archetypal fire-mediated ecosystem that has been the focus of landscape-level restoration in the Southeast. Although historically fires predominately occurred during the growing season in these systems, dormant-season fire is more widely utilized for easier application and control as a means of habitat management in the region. To assess the impacts of fire and environmental factors on bat activity on Camp Blanding Joint Training Center (CB) in northern Florida, USA, we deployed 34 acoustic detectors across CB and recorded data from 26 February to 3 April 2019, and from 10 December 2019 to 14 January 2020. Results We identified eight bat species native to the region as present at CB. Bat activity was related to the proximity of mesic habitats as well as the presence of pine or deciduous forest types, depending on species morphology (i.e., body size, wing-loading, and echolocation call frequency). Activity for all bat species was influenced positively by either time since fire or mean fire return interval. Conclusion Overall, our results suggested that fire use provides a diverse landscape pattern at CB that maintains mesic, deciduous habitat within the larger pine forest matrix, thereby supporting the diverse bat community at CB during the dormant season and early spring.

scholarly journals Exogenous melatonin improves the salt tolerance of cotton by removing active oxygen and protecting photosynthetic organs

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Dan Jiang ◽  
Bin Lu ◽  
Liantao Liu ◽  
Wenjing Duan ◽  
Yanjun Meng ◽  
...  
Keyword(s):  
Salt Stress ◽  
Salt Tolerance ◽  
Oxidative Damage ◽  
Photosynthetic Capacity ◽  
Photochemical Efficiency ◽  
Photochemical Quenching ◽  
Plant Tolerance ◽  
Signal Molecule ◽  
Ion Balance ◽  
Photosynthetic System

Abstract Background As damage to the ecological environment continues to increase amid unreasonable amounts of irrigation, soil salinization has become a major challenge to agricultural development. Melatonin (MT) is a pleiotropic signal molecule and indole hormone, which alleviates the damage of abiotic stress to plants. MT has been confirmed to eliminate reactive oxygen species (ROS) by improving the antioxidant system and reducing oxidative damage under adversity. However, the mechanism by which exogenous MT mediates salt tolerance by regulating the photosynthetic capacity and ion balance of cotton seedlings still remains unknown. In this study, the regulatory effects of MT on the photosynthetic system, osmotic modulators, chloroplast, and anatomical structure of cotton seedlings were determined under 0–500 μM MT treatments with salt stress induced by treatment with 150 mM NaCl. Results Salt stress reduces the chlorophyll content, net photosynthetic rate, stomatal conductance, intercellular CO2 concentration, transpiration rate, PSII photochemical efficiency, PSII actual photochemical quantum yield, the apparent electron transfer efficiency, stomata opening, and biomass. In addition, it increases non-photochemical quenching. All of these responses were effectively alleviated by exogenous treatment with MT. Exogenous MT reduces oxidative damage and lipid peroxidation by reducing salt-induced ROS and protects the plasma membrane from oxidative toxicity. MT also reduces the osmotic pressure by reducing the salt-induced accumulation of Na+ and increasing the contents of K+ and proline. Exogenous MT can facilitate stomatal opening and protect the integrity of cotton chloroplast grana lamella structure and mitochondria under salt stress, protect the photosynthetic system of plants, and improve their biomass. An anatomical analysis of leaves and stems showed that MT can improve xylem and phloem and other properties and aides in the transportation of water, inorganic salts, and organic substances. Therefore, the application of MT attenuates salt-induced stress damage to plants. Treatment with exogenous MT positively increased the salt tolerance of cotton seedlings by improving their photosynthetic capacity, stomatal characteristics, ion balance, osmotic substance biosynthetic pathways, and chloroplast and anatomical structures (xylem vessels and phloem vessels). Conclusions Our study attributes help to protect the structural stability of photosynthetic organs and increase the amount of material accumulation, thereby reducing salt-induced secondary stress. The mechanisms of MT-induced plant tolerance to salt stress provide a theoretical basis for the use of MT to alleviate salt stress caused by unreasonable irrigation, fertilization, and climate change.

scholarly journals Early Spring Snowmelt and Summer Droughts Strongly Impair the Resilience of Key Microbial Communities in Subalpine Grassland Ecosystems

2021 ◽  
Author(s):  
Farhan Hafeez ◽  
Lionel Bernard ◽  
Jean-Christophe Clement ◽  
Franck Poly ◽  
Thomas Pommier
Keyword(s):  
Microbial Communities ◽  
Plant Biomass ◽  
Early Spring ◽  
Climatic Extremes ◽  
Soil Microbial ◽  
Cascading Effect ◽  
Growing Seasons ◽  
Grassland Ecosystems ◽  
Microbial Responses ◽  
Early Snowmelt

Subalpine grassland ecosystems are important from biodiversity, agriculture, and touristic perspectives but their resilience to seasonally occurring climatic extremes is increasingly challenged with climate change, accelerating their vulnerability to tipping points. Microbial communities, which are central in ecosystem functioning, are usually considered as more resistant and highly resilient to such extreme events due to their functional redundancy and strong selection in residing habitats. To investigate this, we explored the soil microbial responses upon recurrent summer droughts associated with early snowmelt in grasslands mesocosms set-up at the Lautaret Pass (French Alps). Potential respiration, nitrification and denitrification were monitored over a period of two growing seasons along with quantification of community gene abundances of total bacteria as well as (de)nitrifiers. Results revealed that droughts had a low and short-term impact on bacterial total respiration supporting their hypothesized high resistance and ability to recover. Nitrification and abundances of the corresponding functional guilds showed relatively strong resistance to summer droughts but declined in response to early snowmelt. This triggered a cascading effect on denitrification but also on the abundances of denitrifying communities which could recover from all climatic extremes except from the summer droughts where nitrifiers were collapsed. Denitrification and the respective functional groups faced high impact of applied stresses with strong reduction in the abundance and activity of this specialized community. Although, the consequently lower microbial competition for nitrate may be positive for plant biomass production, warnings exist when considering the potential nitrogen leaching from these ecosystems as well as risks of greenhouses gases emission such as N2O

scholarly journals Size-dependent susceptibility of lake phytoplankton to light stress: An implication for succession of large green algae in a deep oligotrophic lake

2021 ◽  
Author(s):  
Takehiro Kazama ◽  
Kazuhide Hayakawa ◽  
Takamaru Nagata ◽  
Koichi Shimotori ◽  
Akio Imai ◽  
...  
Keyword(s):  
Algal Blooms ◽  
Light Stress ◽  
Photochemical Efficiency ◽  
Early Summer ◽  
Photochemical Quenching ◽  
P Deficiency ◽  
Chl A ◽  
Psii Photochemistry ◽  
Small Phytoplankton ◽  
Nutrient Bioassay

Field observations of the population dynamics and measurements of photophysiology in Lake Biwa were conducted by size class (< vs. > 30 μm) from early summer to autumn to investigate the relationships between susceptibility to light stress and cell size. Also, a nutrient bioassay was conducted to clarify whether the growth rate and photosystem II (PSII) photochemistry of small and large phytoplankton are limited by nutrient availability. Large phytoplankton, which have lower intracellular Chl-a concentrations, had higher maximum PSII photochemical efficiency (Fv/Fm) but lower non-photochemical quenching (NPQNSV) than small phytoplankton under both dark and increased light conditions. The nutrient bioassay revealed that the PSII photochemistry of small phytoplankton was restricted by N and P deficiency at the pelagic site even at the end of the stratification period, while that of large phytoplankton was not. These results suggest that large phytoplankton have lower susceptibility to PSII photodamage than small phytoplankton due to lower intracellular Chl-a concentrations. The size dependency of susceptibility to PSII photoinactivation may play a key role in large algal blooms in oligotrophic water.

scholarly journals Effects of Different Shading Rates on the Photosynthesis and Corm Weight of Konjac Plant

2019 ◽  
Vol 47 (3) ◽  
Author(s):  
Yaoguo QIN ◽  
Zesheng YAN ◽  
Honghui GU ◽  
Zhengxiang WANG ◽  
Xiong JIANG ◽  
...  
Keyword(s):  
Photosynthetic Efficiency ◽  
Daily Variation ◽  
Photochemical Efficiency ◽  
High Yield ◽  
Photochemical Quenching ◽  
Digital Object Identifier ◽  
Chlorophyll Fluorescence Parameters ◽  
Relative Electron ◽  
Comprehensive Comparison ◽  
Non Photochemical Quenching

To study the effects of shading level on the photosynthesis and corm weight of konjac plant, the chlorophyll fluorescence parameters, daily variation of relative electron transport rate (rETR), net photosynthetic rate (Pn), and corm weight of konjac plants under different treatments were measured and comparatively analyzed through covered cultivation of biennial seed corms with shade nets at different shading rates (0%, 50%, 70%, and 90%). The results showed that with the increase in shading rate, the maximum photochemical efficiency, potential activity, and non-photochemical quenching of photosystem Ⅱ (PSⅡ) of konjac leaves constantly increased, whereas the actual photosynthetic efficiency, rETR, and photochemical quenching of PSⅡ initially increased and then decreased. This result indicated that moderate shading could enhance the photosynthetic efficiency of konjac leaves. The daily variation of rETR in konjac plants under unshaded treatment showed a bimodal curve, whereas that under shaded treatment displayed a unimodal curve. The rETR of plants with 50% treatment and 70% treatment was gradually higher than that under unshaded treatment around noon. The moderate shading could increase the Pn of konjac leaves. The stomatal conductance and transpiration rate of the leaves under shaded treatment were significantly higher than those of the leaves under unshaded treatment. Shading could promote the growth of plants and increase corm weight. The comprehensive comparison shows that the konjac plants had strong photosynthetic capacity and high yield when the shading rate was 50%-70% for the area.   ********* In press - Online First. Article has been peer reviewed, accepted for publication and published online without pagination. It will receive pagination when the issue will be ready for publishing as a complete number (Volume 47, Issue 3, 2019). The article is searchable and citable by Digital Object Identifier (DOI). DOI link will become active after the article will be included in the complete issue. *********

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