Delaying effect of humidity on leaf unfolding in Europe

2021 ◽  
pp. 149563
Author(s):  
Xujian He ◽  
Shanshan Chen ◽  
Jinmei Wang ◽  
Nicholas G. Smith ◽  
Sergio Rossi ◽  
...  
Keyword(s):  
Leaf Unfolding

Cyclamen Leaf Unfolding Rate in Response to Temperature

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 447d-447
Author(s):  
Meriam Karlsson ◽  
Jeffrey Werner
Keyword(s):  
Day Length ◽  
Leaf Number ◽  
Cyclamen Persicum ◽  
Flower Buds ◽  
Flower Bud ◽  
Leaf Unfolding ◽  
Significant Difference ◽  
Number Of Leaves ◽  
Growth Chambers ◽  
Response To Temperature

Nine-week-old plants of Cyclamen persicum `Miracle Salmon' were transplanted into 10-cm pots and placed in growth chambers at 8, 12, 16, 20, or 24 °C. The irradiance was 10 mol/day per m2 during a 16-h day length. After 8 weeks, the temperature was changed to 16 °C for all plants. Expanded leaves (1 cm or larger) were counted at weekly intervals for each plant. The rate of leaf unfolding increased with temperature to 20 °C. The fastest rate at 20 °C was 0.34 ± 0.05 leaf/day. Flower buds were visible 55 ± 7 days from start of temperature treatments (118 days from seeding) for the plants grown at 12, 16, or 20 °C. Flower buds appeared 60 ± 6.9 days from initiation of treatments for plants grown at 24 °C and 93 ± 8.9 days for cyclamens grown at 8 °C. Although there was no significant difference in rate of flower bud appearance for cyclamens grown at 12, 16, or 20 °C, the number of leaves, flowers, and flower buds varied significantly among all temperature treatments. Leaf number at flowering increased from 38 ± 4.7 for plants at 12 °C to 77 ± 8.3 at 24 °C. Flowers and flower buds increased from 18 ± 2.9 to 52 ± 11.0 as temperature increased from 12 to 24 °C. Plants grown at 8 °C had on average 6 ± 2 visible flower buds, but no open flowers at termination of the study (128 days from start of treatments).

scholarly journals Leaf unfolding of Tibetan alpine meadows captures the arrival of monsoon rainfall

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Ruicheng Li ◽  
Tianxiang Luo ◽  
Thomas Mölg ◽  
Jingxue Zhao ◽  
Xiang Li ◽  
...  
Keyword(s):  
Monsoon Rainfall ◽  
Alpine Meadows ◽  
Leaf Unfolding

LIGHT-STIMULATED LEAF GROWTH ON INTACT AND EXCISED BEAN PLANTS (PHASEOLUS VULGARIS L.). II. EFFECT OF LIGHT DURATION AND TIMING OF APPLICATION

1999 ◽  
Vol 47 (3) ◽  
pp. 147-152
Author(s):  
Shimon Lavee ◽  
Elizabeth Van Volkenburgh ◽  
Robert E. Cleland
Keyword(s):  
Phaseolus Vulgaris ◽  
White Light ◽  
Leaf Growth ◽  
Relative Rate ◽  
Red Light ◽  
Leaf Expansion ◽  
Leaf Elongation ◽  
Leaf Unfolding ◽  
Light Duration ◽  
Partial Unfolding

The dependence of bean (Phaseolus vulgaris L. cv. Contender) leaf unfolding and expansion on light has been explored in intact and excised plants by varying the duration and timing of exposure to white light. Plants were grown for 10 days in dim red light (RL), and then some were excised. Both the intact and the excised plants were then exposed to varying white light (WL) treatments. In continuous WL, leaf unfolding began after 8 h, and was maximal after 36 h. For plants exposed to short WL treatments, as little as 2 h WL elicited partial unfolding when leaves were returned to RL and measured after 60 h. The relative rate of leaf elongation was most rapid during the first 2 h of WL and it rapidly decreased during the following 6–8 h. An 8 h exposure to WL followed by 52 h RL produced only a slightly lower leaf expansion than continuous WL for 32 h. Leaf elongation after 24 h constant WL irradiance was no longer light-dependent. The response of leaves on excised plants to WL was progressively less if treatment was delayed for 24 h after excision. In contrast, leaves on intact plants did not lose their ability to respond to light even after 48 h in the dark. The ability of leaves on intact or excised plants to elongate in RL decayed rapidly after day 10. These results indicate that light-stimulated leaf expansion in beans is mediated by some factors whose transport to the leaves is influenced by the presence of roots.

Variability of green-up duration of deciduous broadleaf forests in Central Europe during 2000-2019 based on MODIS NDVI

2020 ◽  
Author(s):  
Anikó Kern ◽  
Hrvoje Marjanović ◽  
Zoltán Barcza
Keyword(s):  
Land Cover ◽  
Central Europe ◽  
Vegetation Index ◽  
Meteorological Conditions ◽  
Extreme Weather Events ◽  
Canopy Conductance ◽  
Linear Regression Models ◽  
Leaf Unfolding ◽  
Modis Ndvi ◽  
Vegetation Activity

<p>Spring leaf unfolding is a spectacular recurring event at the mid- and high latitudes that is associated with deciduous vegetation. Several lines of evidence indicate that the timing of spring green-up (i.e. the start of the season, SOS) changed in the past decades resulting in an earlier leaf unfolding - a phenomenon which is considered to be a major indicator of the effects of global warming. Contrary to the timing of the SOS, considerably less attention was paid to studying the dynamics of vegetation green-up, characterized by the leaf unfolding speed or the duration of spring green-up. The importance of studying the spring green-up dynamics lies in the fact that the duration of leaf development and timing of the onset of growth jointly determine the annual cycle of vegetation activity including carbon and energy balance, canopy conductance and evapotranspiration.</p><p>The aim of our research was to characterize the dynamics of leaf unfolding of deciduous broadleaf forests in the wider Carpathian Basin, located in Central Europe, using satellite remote sensing. The study was based on the Normalized Difference Vegetation Index (NDVI) time-series derived from the MOD09A1 official MODIS products during 2000–2019, the IGBP land cover classification dataset of the MCD12Q1 products, the CORINE 2012 (CLC2012) land cover dataset, the SRTM elevation dataset, and the FORESEE meteorological database. Our results clearly show that there is considerable interannual variability in the green-up duration of the deciduous broadleaf forest during 2000–2019. The last three years had, on average, the shortest (2018) and the two longest (2017 and 2019) recorded green-up durations in the region. Observed variability was partially attributed to the meteorological conditions, namely the extreme weather events occurring during the spring. We demonstrate that the meteorological conditions during the green-up period have a strong effect on the duration. The relationship between the SOS and the green-up duration reveals that the SOS also played an important role as a driver. Our results also reveal considerable elevation dependency both in the green-up duration and also in its correlation with SOS. Multiple linear regression models based on the SOS and the meteorological variables were also created to explain and predict the green-up duration.</p>

scholarly journals Three times greater weight of daytime than of night-time temperature on leaf unfolding phenology in temperate trees

2016 ◽  
Vol 212 (3) ◽  
pp. 590-597 ◽  
Author(s):  
Yongshuo H. Fu ◽  
Yongjie Liu ◽  
Hans J. De Boeck ◽  
Annette Menzel ◽  
Ivan Nijs ◽  
...  
Keyword(s):  
Night Time ◽  
Leaf Unfolding ◽  
Temperate Trees

Effect of Leaf Position, Expansion and Age on Photosynthesis, Transpiration and Water Use Efficiency of Cotton

1980 ◽  
Vol 7 (1) ◽  
pp. 89 ◽  
Author(s):  
GA Constable ◽  
HM Rawson
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Dark Respiration ◽  
Vapour Pressure Deficit ◽  
Initial Slope ◽  
Photon Flux ◽  
Morphological Development ◽  
Leaf Position ◽  
Leaf Unfolding ◽  
Use Efficiency

Net photosynthesis, dark respiration and the response to photon flux density were measured on cotton leaves grown in a glasshouse. Leaves at four positions on the plant were examined from their unfolding until 70 days later. Photosynthesis and transpiration per unit of leaf area were unaffected by leaf position and, in all leaves, peak photosynthesis of about 110 ng CO2 cm-2 s-1 was attained 13-15 days after leaf unfolding, when the leaf was 75-90% of maximum area. Photosynthesis was maintained at this rate for only 12 days before declining linearly to values 20% of the maximum when leaves were 70 days old. Transpiration followed a similar pattern reaching a maximum of about 13 �g H2O cm-2 s-1 at 2 kPa vapour pressure deficit (VPD) at 13 days. Stomatal and internal conductances changed in parallel as leaves aged, with the consequence that internal CO2 concentration and water use efficiency remainedessentially constant at 220�ll-1 and 16.8 ng CO2 (�g H2O kPa VPD-1)-1 respectively. Youngest and oldest leaves saturated at lowest light levels (400-800 pE m-2 s-1) while 16-18- day-old leaves had light saturation at 1100 �E m-2 s-1. The initial slope of the light response curves increased as leaves expanded up to 10 days age then remained constant at 0.25 ng CO2 cm-2 (pE m-2)-1. Dark respiration reached a maximum of 1.5 ng CO2 mg-1 s-1 5 days after leaf unfolding, when leaf dry weight was increasing most rapidly. The relationship between the consistent pattern of gas exchange with age and the pattern of morphological development is discussed, along with internal factors associated with age-dependent photosynthesis.

scholarly journals Temperature Affects Leaf Unfolding Rate and Flowering of Cyclamen

HortScience ◽  
2001 ◽  
Vol 36 (2) ◽  
pp. 292-294 ◽  
Author(s):  
Meriam Karlsson ◽  
Jeffrey Werner
Keyword(s):  
Dry Weight ◽  
Similar Rate ◽  
Flower Number ◽  
Flower Buds ◽  
Open Flower ◽  
Leaf Unfolding ◽  
Response To Temperature ◽  
Relationship Of ◽  
The Relationship ◽  
Large Flower

The rate of leaf unfolding for Cyclamen persicum Mill. was determined at 8 to 24 °C. Temperature treatments started 9 weeks from seeding and after 8 weeks all plants were moved to 16 °C. The cultivars Miracle Salmon, Miracle Scarlet, and Miracle White produced leaves at a similar rate. The relationship of (leaves/d) = - 0.01727 - 0.02284 * °C + 0.005238 * (°C)2 - 0.000162 * (°C)3 (R2 = 0.99) best described the leaf unfolding rate in response to temperature. The maximum leaf unfolding rate was estimated to 0.329 leaves/day at 19.1 °C. Flower buds (2 mm diameter) developed within 60 days from the start of temperature treatments except at 8 °C. Thirty-five additional days at 16 °C were required for cyclamen initially grown at 8 °C for 8 weeks to produce flower buds. Despite similar conditions during bud development, flowering was delayed 14 to 18 days for plants initially grown at 24 °C compared to those grown at 12 to 20 °C. Plants initially at 8 °C did not flower within 70 days at 16 °C. Leaf and flower numbers at first open flower increased as initial temperature increased from 12 to 24 °C while dry weight and height only increased to 20 °C. No correlation between leaf unfolding and rate of flowering or flower number was detected. Recommendations for 20 °C during early cyclamen growth can be expected to support rapid rates of leaf unfolding and development, and large flower numbers.

scholarly journals The Effect of Temperature on Leaf and Flower Development and Flower Longevity of Zygopetalum Redvale `Fire Kiss' Orchid

HortScience ◽  
2004 ◽  
Vol 39 (7) ◽  
pp. 1630-1634 ◽  
Author(s):  
Roberto G. Lopez ◽  
Erik S. Runkle
Keyword(s):  
Effect Of Temperature ◽  
Controlled Environment ◽  
Base Temperature ◽  
Flower Longevity ◽  
Open Flower ◽  
Leaf Unfolding ◽  
Expansion Time ◽  
Different Temperatures ◽  
Plant Characteristics ◽  
Greenhouse Growers

The vegetatively propagated `Fire Kiss' clone of the hybrid Zygopetalum Redvale orchid has appealing potted-plant characteristics, including fragrant flowers that are waxy lime-green and dark maroon with a broad, three-lobed, magenta and white labellum. We performed experiments to quantify how temperature influenced leaf unfolding and expansion, time from visible inflorescence to flower, and longevity of individual flowers and inflorescences. Plants were grown in controlled-environment chambers with constant temperature set points of 14, 17, 20, 23, 26, and 29 °C and an irradiance of 150 μmol·m-2·s-1 for 9 h·d-1. As actual temperature increased from 14 to 25 °C, the time to produce one leaf decreased from 46 to 19 days. Individual plants were also transferred from a greenhouse to the chambers on the date that an inflorescence was first visible or the first flower of an inflorescence opened. Time from visible inflorescence to open flower decreased from 73 days at 14 °C to 30 days at 26 °C. As temperature increased from 14 to 29 °C, flower and inflorescence longevity decreased from 37 and 38 days to 13 and 15 days, respectively. Data were converted to rates, and thermal time models were developed to predict time to flower and senescence at different temperatures. The base temperature was estimated at 6.2 °C for leaf unfolding, 3.5 °C for time to flower, and 3.7 °C for flower longevity. These models could be used by greenhouse growers to more accurately schedule Zygopetalum flowering crops for particular market dates.

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