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.

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.

EARLYWOOD VESSELS IN RING-POROUS TREES BECOME FUNCTIONAL FOR WATER TRANSPORT AFTER BUD BURST AND BEFORE THE MATURATION OF THE CURRENT-YEAR LEAVES

IAWA Journal ◽  
2016 ◽  
Vol 37 (2) ◽  
pp. 315-331 ◽  
Author(s):  
Peter Kitin ◽  
Ryo Funada
Keyword(s):  
Water Transport ◽  
Time Course ◽  
Growing Season ◽  
Early Spring ◽  
Vessel Element ◽  
Full Time ◽  
Bud Burst ◽  
Long Time ◽  
Wall Perforation ◽  
Earlywood Vessels

This paper reviews the development of xylem vessels in ring-porous dicots and the corresponding leaf phenology. Also included are our original observations on the time-course of vessel element growth, secondary wall deposition, and end wall perforation in the deciduous hardwood Kalopanax septemlobus. Different patterns of xylem growth and phenology serve different strategies of the species for adaptation to seasonal climates. Trees with ring-porous xylem form wide earlywood vessels (EWV) in spring and narrow latewood vessels in summer. The wide EWV become embolized or blocked with tyloses by the end of the growing season while the narrow vessels may remain functional for many years. The co-occurrence of wide and narrow vessels provides both efficiency and safety of the water transport as well as a potentially longer growing season. It has for a long time been assumed that EWV in ring-porous hardwoods are formed in early spring before bud burst in order to supply sap to growing leaves and shoots.However, the full time-course of development of EWV elements from initiation of growth until maturation for water transport has not been adequately studied until recently. Our observations clarify a crucial relationship between leaf maturation and the maturation of earlywood vessels for sap transport. Accumulated new evidence shows that EWV in branches and upper stem parts develop earlier than EWV lower in the stem. The first EWV elements are fully expanded with differentiated secondary walls by the time of bud burst. In lower stem parts, perforations in vessel end walls are formed after bud burst and before the new leaves have achieved full size. Therefore, the current-year EWV network becomes functional for water transport only by the time when the first new leaves are mature.

scholarly journals Competition for Light Affects Alfalfa Biomass Production More Than Its Nutritive Value in an Olive-Based Alley-Cropping System

Forests ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 233
Author(s):  
Alberto Mantino ◽  
Cristiano Tozzini ◽  
Enrico Bonari ◽  
Marcello Mele ◽  
Giorgio Ragaglini
Keyword(s):  
Biomass Production ◽  
Nutritive Value ◽  
Alley Cropping ◽  
Light Availability ◽  
Agroforestry Systems ◽  
Tree Canopy ◽  
Soil Protection ◽  
Olive Orchard ◽  
Competition For Light ◽  
Perennial Legumes

Cropping among trees with perennial legumes is one option for increasing agro-ecosystem services, such as improving the nitrogen supply and increasing soil protection by herbaceous vegetation. Moreover, cropping under the canopy of olive trees should diversify the farm production, compared to the traditional fallow management. Among perennial legumes, alfalfa (Medicago sativa L.) produces abundant biomass under Mediterranean rainfed condition. Based on this, a two-year field experiment was implemented in southern Tuscany in a rainfed olive orchard to test the competition for light effects on alfalfa biomass production and nutritive value. Light availability under the tree canopy was measured by hemispherical photos. In both years, the alfalfa yield of under-canopy varied according to the tree presence. A significant relationship between biomass production and light availability was recorded. The nutritive value of under-canopy alfalfa was similar to that of the open-grown alfalfa. However, same significant differences did however occur, between shaded and sole crop. When differences were found, under-canopy herbage was characterised by a higher content of crude protein and a lower content of fibre with respect to open-grown. In a hilly silvoarable olive orchard, alfalfa biomass accumulation was reduced mainly due to scarce light availability, therefore tree management such as pruning and plantation layout can enhance the herbage productivity. Studying shade tolerant forage legumes in order to enhance the yield and nutritive value of herbage production in rainfed agroforestry systems is essential.

scholarly journals Increase in perennial forage yields driven by climate change, at Apukka Research Station, Rovaniemi, 1980-2017

2020 ◽  
Vol 29 (2) ◽  
Author(s):  
Oiva Niemeläinen ◽  
Antti Hannukkala ◽  
Lauri Jauhiainen ◽  
Kaija Hakala ◽  
Markku Niskanen ◽  
...  
Keyword(s):  
Climate Change ◽  
Festuca Arundinacea ◽  
Ground Cover ◽  
Growing Season ◽  
Phleum Pratense ◽  
Research Station ◽  
Strong Impact ◽  
Meadow Fescue ◽  
Forage Crops ◽  
The North

The official variety trials at Rovaniemi, Finland (66.58°N, 26.01°E) in 1980–2017 show a substantial increase in dry matter yields (DMY) of timothy (Phleum pratense), meadow fescue (Festuca pratensis) and tall fescue (Festuca arundinacea), coinciding with a 156 °Cd increase in the average growing season Tsum and a 461 °Cd decrease in the average winter frost sum for the same period. The annual DMY of timothy was 3128, 4668, 8385 and 9352 kg ha-1 in the periods (P) 1980–1989 (P1), 1990–1999 (P2), 2000–2009 (P3), and 2010–2017 (P4). The first cut yielded 1792, 2166, 4008 and 4473, and the second cut 1337, 2503, 4378 and 4879 kg ha-1, respectively. Yields of meadow fescue followed a similar pattern. The first cut was about ten days and the second cut about one week earlier on P4 than on P1. Shorter snow cover period, milder winters, higher live ground cover of timothy in spring, and higher temperature sum during the growing season were most likely responsible for the yield increase. The results indicate a strong impact of climate change on DMY of perennial forage crops in the north.

The Incidence of Climatic Conditions Favourable to Coffee Berry Disease in Kenya

1971 ◽  
Vol 7 (4) ◽  
pp. 303-314 ◽  
Author(s):  
J. M. Waller
Keyword(s):  
Air Temperature ◽  
Spore Germination ◽  
Growing Season ◽  
Climatic Conditions ◽  
Tree Canopy ◽  
Disease Development ◽  
Spore Dispersal ◽  
Coffee Berry ◽  
Coffee Berry Disease ◽  
Air Temperatures

SUMMARYClimatic conditions affecting the development of CBD are assessed by measuring wetness within the tree canopy and air temperature. Saturation of the tree canopy, necessary for spore dispersal, occurs most frequently at the tops of trees and the duration of wetness permitting spore germination is most prolonged at night. Night air temperatures are closest to berry temperatures and are important in assessing infection periods. Disease development in 1968 and 1969 was related to the number of infection periods during the growing season. Polythene tree covers which kept trees sufficiently dry to stop disease development were used in determining infection at different times of the year.

Juvenile tree growth in relation to light availability in second-growth tropical rain forests

2006 ◽  
Vol 22 (2) ◽  
pp. 223-226 ◽  
Author(s):  
Mary Beth Palomaki ◽  
Robin L. Chazdon ◽  
J. Pablo Arroyo ◽  
Susan G. Letcher
Keyword(s):  
Tropical Forests ◽  
Light Availability ◽  
Tree Seedlings ◽  
Tropical Rain Forests ◽  
Annual Increment ◽  
Growth And Survival ◽  
Second Growth ◽  
Direct Measurements ◽  
Crown Shape ◽  
Made In

Light is a key environmental factor limiting growth and survival of trees in the subcanopy of wet tropical forests (Davies 2001, Thomas 1996). Light availability varies both vertically and horizontally and affects tree height, crown shape and tree architecture (Bongers & Sterck 1998, Sterck & Bongers 2001, Sterck et al. 1999) in addition to growth and survival (Clark & Clark 1992, 2001). Although many studies of tree seedlings and saplings have shown that growth varies significantly with light availability in tropical wet forests (Clark et al. 1993, Iriarte & Chazdon 2005, King 1991, Kohyama 1991, Montgomery & Chazdon 2002, Oberbauer et al. 1988, 1993; Poorter & Werger 1999, Sterck et al. 1999, Welden et al. 1991), few studies have examined these relationships in size classes above 5 cm dbh (Sterck 1999). King et al. (2005) found that annual increment growth of trees in the 8–20-cm dbh size class in two Asian forests was positively dependent on an index of crown light interception, but no direct measurements of light availability were taken in this study. Due to logistical challenges, few direct measurements of light environments above tree crowns have been made in tropical forests (Sterck & Bongers 2001). To our knowledge, no measurements have been made in second-growth forests.

scholarly journals Phenology of hatching, emergence, and end-of-season body size in young-of-year coho salmon in thermally contrasting streams draining the Copper River Delta, Alaska

2019 ◽  
Vol 76 (2) ◽  
pp. 185-191 ◽  
Author(s):  
Emily Y. Campbell ◽  
Jason B. Dunham ◽  
Gordon H. Reeves ◽  
Steve M. Wondzell
Keyword(s):  
Body Size ◽  
Environmental Variability ◽  
Coho Salmon ◽  
Growing Season ◽  
Early Life History ◽  
Growth And Survival ◽  
Individual Fitness ◽  
Marked Variability ◽  
Thermal Regimes ◽  
Body Sizes

Phenology can be linked to individual fitness, particularly in strongly seasonal environments where the timing of events has important consequences for growth, condition, and survival. We studied the phenology of coho salmon (Oncorhynchus kisutch) hatching and emergence in streams with contrasting thermal variability but in close geographic proximity. Following emergence, we tracked body sizes of cohorts of young-of-year fish until the end of the growing season. Hatch and emergence occurred at the same time among streams with marked variability in thermal regimes. We demonstrate that this can be explained in part by the thermal units accumulated during embryo development. At the end of the first growing season, there were some differences in body size, but overall fish size was similar among streams despite strong differences in thermal regimes. Collectively, these results provide novel insights into the interactions between environmental variability and the early life-history stages of coho salmon, furthering our understanding of the consequences of phenology on growth and survival for individuals within the critical first summer of life.

The growth of young peach trees following infection by the viruses of peach rosette and decline disease

1977 ◽  
Vol 28 (3) ◽  
pp. 441 ◽  
Author(s):  
PR Smith ◽  
TF Neales
Keyword(s):  
Leaf Area ◽  
Vegetative Growth ◽  
Virus Disease ◽  
Dry Weight ◽  
Growing Season ◽  
Dual Infection ◽  
Bud Burst ◽  
Decline Disease ◽  
Peach Trees

The vegetative growth of young peach trees was reduced greatly in the growing season following a dual infection with Prunus necrotic ringspot and prune dwarf viruses which caused the disease known as 'peach rosette and decline'. Ninety-two days after bud burst, the dry weight and leaf area of cv. Elberta scions were reduced by c. 60% as a result of infection, while the reduction in cv. Golden Queen was about 93%. The latter cultivar thus appears to be the less tolerant of infection by this virus disease.

Are resources allocated differently to symbiosis and reproduction in Geranium sylvaticum under different light conditions?

2004 ◽  
Vol 82 (1) ◽  
pp. 89-95 ◽  
Author(s):  
Jarkko Korhonen ◽  
Minna-Maarit Kytöviita ◽  
Pirkko Siikamäki
Keyword(s):  
Resource Allocation ◽  
Forest Canopy ◽  
Light Availability ◽  
Growing Season ◽  
High Light ◽  
Mycorrhizal Colonization ◽  
Fungal Colonization ◽  
Low Light ◽  
Light Levels ◽  
Dark Septate Fungi

Light levels under the forest canopy are low and generally limit plant photosynthetic gains. We hypothesized that in low-light habitats, plant photosynthate acquisition is too low to allow the same magnitude of resource allocation to symbiosis and reproduction as in high-light habitats. We tested this hypothesis in a field study where Geranium sylvaticum L. plants were collected on three occasions during the growing season from shade and light habitats. In addition, we investigated the relationship between mycorrhizal colonization level and soil nutrient levels in shade and high-light habitats over a growing season. We found that light availability affects resource allocation in G. sylvaticum. Plants were intensively colonized with both arbuscular mycorrhizal and dark septate fungi, and the colonization intensities of these two different groups of fungi correlated positively with each other. In comparison with high-light meadows, mycorrhizal colonization levels were as high or higher in low-light forest habitats, but plants produced fewer flowers. This indicates that allocation to symbiosis was of higher priority than allocation to reproduction in low light. Seed size was not affected by light levels and did not correlate with fungal colonization levels. We found no relationship between fungal colonization levels and soil characteristics.Key words: arbuscular mycorrhiza, dark septate fungi, Geranium sylvaticum, reproduction, shade.

Bud burst phenology in different poplar and willow clones

2019 ◽  
Vol 79 (3) ◽  
pp. 79-84
Author(s):  
Y. Khoma ◽  
N. Kutsokon
Keyword(s):  
Open Field ◽  
Climate Changes ◽  
Global Climate ◽  
Growing Season ◽  
Test Site ◽  
Botanical Garden ◽  
Light Regime ◽  
Bud Burst ◽  
Experimental Plot ◽  
Poplar Clones

In the face of global climate changes, studies of bud burst and bud set phenology in trees are necessary to determine the duration of the growing season of plants, the optimal planting period, and seasonal works to achieve high productivity. The purpose of our study was to investigate bud burst phenology in different poplar and willow clones, what is important for predicting possible responses of woody plants to climate changes. Materials and methods: Bud burst phenology in poplar and willow was monitored both on the plants growing at experimental plot and on potted plants. Open-field plant research was conducted on a test site of fast-growing bioenergy trees in the M.M. Gryshko National Botanical Garden of NAS of Ukraine (Kyiv). Nine most productive poplar and willow clones were selected for the potted experiment. Throughout the growing season, the plants were kept outdoors, and after the seasonal fall of the leaves, the plants were transferred to an unheated storage room with a limited light regime. During spring, bud burst phenology was screened weekly through 45 days according to the 6-scores scale. The studies showed that the poplar plants grown under laboratory conditions demonstrated faster rates of bud burst compared to the willows, while the plants at the experimental plot, on the contrary, shown faster bud burst in the willows comparing to poplar clones. Such effects may be caused by the restricted light regime at the laboratory space what probably had stronger impact on the bud burst in willows, and in the case of open-field plants also by other random environmental factors. In potted conditions, willows demonstrated a tendency for faster flushing of lateral buds, while most poplar clones showed faster apical bud growth under the same conditions.

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