Hormonal Physiology of Wood Growth in Pinus radiata D. Don: Effects of Gibberellin A4 and the Influence of Abscisic Acid Upon (3H) Gibberellin A4 Metabolism

1981 ◽  
Vol 8 (6) ◽  
pp. 559 ◽  
Author(s):  
RP Pharis ◽  
PA Jenkins ◽  
H Aoki ◽  
T Sassa
Keyword(s):  
Abscisic Acid ◽  
Radial Growth ◽  
Growing Season ◽  
Xylem Cell ◽  
Highly Active ◽  
Long Day ◽  
Amylase Production ◽  
Barley Aleurone ◽  
Low Levels ◽  
Glucosyl Ester

Xylem cell radial growth of 1-year-old seedlings of P. radiata was significantly increased by application of gibberellin A4 (GA4), or of abscisic acid (ABA) plus a smaller, and non-significant, dosage of GA4. In 10 out of 15 additional tests throughout the growing season, ABA tended to increase radial growth, and only once (in mid-summer) did ABA significantly reduce xylem cell radial growth. Seedlings were grown under well watered, warm, long-day conditions. Where GA4 (22 �g) or ABA (20 �g) plus GA4 (2 �g) increased xylem cell radial growth, the metabolism of [3H]GA4 was followed. Although not characterized from P. radiata, GA4 is native to P. attenuata, a species which will hybridize with P. radiata. At low levels (2 �g) of carrier GA4, [3H]GA4 metabolism was rapid, and ABA (20 �g) enhanced metabolism, especially into acidic metabolites. One metabolite was definitively characterized as GA34 and other metabolites eluted in regions of a SiO2 partition column coincidental with GA1, GA2, GAB and GA4 glucosyl ester. At high levels (22 �g) of carrier GA4, [3H]GA4 metabolism was dampened, and ABA reduced the metabolism of [3H]GA4 even further. Enhanced metabolism of [3H]GA4 in P. radiata by ABA is analogous to an earlier report [Nadeau et al. (1972). Planta 107, 315-24] where ABA enhanced the metabolism of [3H]GA1 in barley aleurone layers while reducing their GA1-stimulated amylase production. However, in P. radiata, ABA increased xylem cell radial growth while enhancing [3H]GA4 metabolism. If the metabolites of GA4 that were enhanced by ABA were highly active, a similar effect might also be exerted on endogenous GAs, thus explaining the modest tendency of ABA to promote radial growth through much of the year.

Dynamics of stem radial growth of Picea meyeri during the growing season at the treeline of Luya Mountain, China

2013 ◽  
Vol 36 (9) ◽  
pp. 956-964 ◽  
Author(s):  
Man-Yu DONG ◽  
Yuan JIANG ◽  
Hao-Chun YANG ◽  
Ming-Chang WANG ◽  
Wen-Tao ZHANG ◽  
...  
Keyword(s):  
Radial Growth ◽  
Growing Season

scholarly journals Comparison of the Radial Growth Response of Picea crassifolia to Climate Change in Different Regions of the Central and Eastern Qilian Mountains

Forests ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 1015
Author(s):  
Xuan Wu ◽  
Liang Jiao ◽  
Dashi Du ◽  
Changliang Qi ◽  
Ruhong Xue
Keyword(s):  
Climate Change ◽  
Tree Growth ◽  
Central Region ◽  
Radial Growth ◽  
Growing Season ◽  
Qilian Mountains ◽  
Growth Patterns ◽  
Total Precipitation ◽  
Picea Crassifolia ◽  
The Qilian Mountains

It is important to explore the responses of radial tree growth in different regions to understand growth patterns and to enhance forest management and protection with climate change. We constructed tree ring width chronologies of Picea crassifolia from different regions of the Qilian Mountains of northwest China. We used Pearson correlation and moving correlation to analyze the main climate factors limiting radial growth of trees and the temporal stability of the growth–climate relationship, while spatial correlation is the result of further testing the first two terms in space. The conclusions were as follows: (1) Radial growth had different trends, showing an increasing followed by a decreasing trend in the central region, a continuously increasing trend in the eastern region, and a gradually decreasing trend in the isolated mountain. (2) Radial tree growth in the central region and isolated mountains was constrained by drought stress, and tree growth in the central region was significantly negatively correlated with growing season temperature. Isolated mountains showed a significant negative correlation with mean minimum of growing season and a significant positive correlation with total precipitation. (3) Temporal dynamic responses of radial growth in the central region to the temperatures and SPEI (the standardized precipitation evapotranspiration index) in the growing season were unstable, the isolated mountains to total precipitation was unstable, and that to SPEI was stable. The results of this study suggest that scientific management and maintenance plans of the forest ecosystem should be developed according to the response and growth patterns of the Qinghai spruce to climate change in different regions of the Qilian Mountains.

Nitrogen fixation and photosynthesis in high arctic forms of Nostoc commune

1994 ◽  
Vol 72 (7) ◽  
pp. 940-945 ◽  
Author(s):  
R. Lennihan ◽  
D. M. Chapin ◽  
L. G. Dickson
Keyword(s):  
Nitrogen Fixation ◽  
Acetylene Reduction ◽  
Terrestrial Ecosystems ◽  
Growing Season ◽  
High Arctic ◽  
Colony Morphology ◽  
Nostoc Commune ◽  
Devon Island ◽  
Low Levels ◽  
Temperature Optima

Nostoc commune, a colonial cyanobacterium, has been suggested as an important contributor of nitrogen to terrestrial ecosystems in the Canadian High Arctic, yet little is known about the ecophysiology of this organism in arctic environments. This study focused on the physiological performance of macroscopic colonies of N. commune found on Devon Island, N.W.T. The objectives were to examine the influence of temperature, colony morphology, and seasonal phenology on nitrogen fixation rates and the effects of light and temperature on photosynthesis. Maximum rates of acetylene reduction in N. commune (2119 nmol C2H4∙g−1∙h−1) were higher than those previously recorded for arctic N. commune but lower than values reported for temperate poulations. Depending on the time of the growing season, the temperature optimum for acetylene reduction varied from 15 °C to greater than 20 °C. Photosynthetic temperature optima did not occur below 20–25 °C (the highest temperatures measured). Light saturation of photosynthesis was reached at low levels of irradiance (100–150 μmol∙m−2∙s−1 PPFD). Acetylene reduction rates varied strongly with colony morphology. Thin, fragile, flattened colonies had higher rates than thicker, more resilient, flattened colonies or spherical colonies. Cold post-thaw temperatures appeared to delay the recovery of maximum nitrogen fixation rates for 2–3 weeks following the onset of the growing season. Compared with two other species of cyanobacteria present on Truelove Lowland (Gloeocapsa alpina and Gleotrichia sp.), N. commune had higher rates of nitrogen fixation. Key words: Nostoc commune, cyanobacteria, High Arctic, nitrogen fixation, photosynthesis.

scholarly journals Main features of Poaceae pollen season in Madeira region (Portugal)

2015 ◽  
Vol 68 (4) ◽  
pp. 367-372
Author(s):  
Irene Câmara Camacho ◽  
Rita Câmara ◽  
Roberto Camacho
Keyword(s):  
Pollen Season ◽  
Airborne Pollen ◽  
Growing Season ◽  
Onset Date ◽  
Critical Levels ◽  
Pollen Monitoring ◽  
Madeira Island ◽  
Poaceae Pollen ◽  
The Mean ◽  
Low Levels

<p>The pollinic spectrum of the Madeira region is dominated by grass pollen, which also represents an important aeroallergen in Europe. The present work aims to analyze the main features of the Poaceae pollen season in the Madeira region to determine the allergic risk. The study took place in Funchal city, the capital of Madeira Island, over a period of 10 years (2003–2012). The airborne pollen monitoring was carried out with a Hirst type volumetric trap, following well-established guidelines.</p><p>In the atmosphere of Funchal, the mean annual Poaceae pollen index was 229. The mean Poaceae pollen season lasts 275 days, with an onset date in January/March and an end date in November/December. Poaceae counts showed a seasonal variation with 2 distinct peaks: a higher peak between March and June, and the second one in autumn. The peak values occurred mainly between April and June, and the highest peak was 93 grains/m<sup>3</sup>, detected on the 27th May of 2010. The Poaceae pollen remaining at low levels during the whole growing season, presenting a nil to low allergenic risk during most of the study period. Higher critical levels of allergens have been revealed after 2006. In general, the pollen risk from Poaceae lasted only a few days per year, despite the very long pollen season and the abundance of grasses in the landscape of Madeira Island.</p>

Flowering of Stylosanthes guianensis in controlled temperatures under natural photoperiod

1984 ◽  
Vol 35 (2) ◽  
pp. 219 ◽  
Author(s):  
RL Ison ◽  
LR Humphreys
Keyword(s):  
Floral Initiation ◽  
Minimum Duration ◽  
Stylosanthes Guianensis ◽  
Short Day ◽  
Long Day ◽  
Natural Photoperiod ◽  
Low Levels ◽  
Short Days

Seedlings of Stylosanthes guianensis var. guianensis cv. Cook and cv. Endeavour were grown in naturally lit glasshouses at Brisbane (lat. 27� 30' S.) at 35/30, 30/25 and 25/20�C (day/night), and were sown so as to emerge at 18-day intervals from 18 January to 11 June. Cook behaved as a long day-short day plant, with seedlings emerging after 5 February flowering incompletely or remaining vegetative until the experiment was terminated in mid-October. In the 25/20�C regimen flowering was incomplete in Cook; in Endeavour flowering was delayed but a conventional short-day response was observed. At 35/30�C Endeavour flowering was inhibited in the shortest days of mid-winter, suggesting a stenophotoperiodic response, but short days were confounded with low levels of irradiance. Minimum duration of the phase from emergence to floral initiation was c. 66-70 days in Cook and c. 40-45 days in Endeavour; the duration of the phase floral initiation to flower appearance was linearly and negatively related to temperature.

Inhibition of Flowering in Lolium temulentum L. By Water Stress: a Role for Abscisic Acid

1977 ◽  
Vol 4 (2) ◽  
pp. 225 ◽  
Author(s):  
RW King ◽  
LT Evans
Keyword(s):  
Abscisic Acid ◽  
Water Stress ◽  
Long Day ◽  
Relative Water ◽  
The One ◽  
Floral Evocation ◽  
Leaf Photosynthetic Rate ◽  
Response To Water ◽  
Aba Content ◽  
High Intensity Light

A brief, 8-h water stress during the induction of flowering in L. temulentum reduces the flowering response, the more so the greater the stress. Water stress also affected leaf photosynthetic rate, relative water content of leaves and leaf elongation. Water stress was most inhibitory to flowering when applied during the period of high-intensity light at the beginning of the one long day. The abscisic acid (ABA) content of leaves increased up to 30-fold during the imposition of water stress and fell rapidly after stress was relieved, regardless of when the stress was imposed. The greater the stress, the higher was the level of ABA in leaves and the greater was the inhibition of flowering. The ABA content of apices also rose in response to water stress, in some cases during the stress treatment but usually 8-22 h later. Flowering was inhibited when apical ABA contents were high at the end of the long day. Although water stress may influence the flowering of plants in several ways, these experiments suggest that water stress during the long day induction of L. temulentum inhibits flowering by raising the content of ABA at the shoot apex during floral evocation.

scholarly journals Deep Sequencing and Analysis of Transcriptomes of Pinus koraiensis Sieb. & Zucc.

Forests ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 350
Author(s):  
Shaolin Shi ◽  
Siyu Yan ◽  
Chao Zhao ◽  
Peng Zhang ◽  
Ling Yang ◽  
...  
Keyword(s):  
Abscisic Acid ◽  
Differentially Expressed Genes ◽  
Pathway Analysis ◽  
Deep Sequencing ◽  
Transcriptome Sequencing ◽  
Enrichment Analysis ◽  
Reproductive Development ◽  
Pinus Koraiensis ◽  
Apical Buds ◽  
Low Levels

The objective of this research was to study the differences in endogenous hormone levels and the genes related to reproductive development in Chinese pinenut (Pinus koraiensis) trees of different ages. The apical buds of P. koraiensis were collected from 2-, 5-, 10-, 15-, and 30-year-old plants and also from grafted plants. There were three replicates from each group used for transcriptome sequencing. After assembly and annotation, we identified the differentially expressed genes (DEGs) and performed enrichment analysis, pathway analysis, and expression analysis of the DEGs in each sample. The results showed that unigenes related to reproductive development, such as c64070.graph_c0 and c68641.graph_c0, were expressed at relatively low levels at young ages, and that the relative expression gradually increased with increasing plant age. In addition the highest expression levels were reached around 10 and 15 years of age, after which they gradually decreased. Moreover, some unigenes, such as c61855.graph_c0, were annotated as abscisic acid hydroxylase genes, and the expression of c61855.graph_c0 gradually declined with increasing age in P. koraiensis.

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