scholarly journals The effect of the photoperiod on the level of endogenous growth regulators in pine (Pinus silvestris L.) seedlings

2014 ◽  
Vol 51 (1) ◽  
pp. 59-70 ◽  
Author(s):  
Krystyna Kriesel ◽  
Sławomir Ciesielska
Keyword(s):  
Abscisic Acid ◽  
Growth And Development ◽  
Morphological Characters ◽  
Axillary Buds ◽  
Pinus Silvestris ◽  
Low Intensity ◽  
Pine Seedlings ◽  
Terminal Bud ◽  
Development Processes ◽  
High Level

The investigations were performed on pine seedlings growing under 12, 16 and 20 hour photoperiods. In 4 succesive stages of seedling development i.e. after 2, 12, 18 and 30 weeks of culture morphological characters of the seedlings were measured and the levels of auxins-, gibberellins-, cytokininsand abscisic acid-like inhibitor were determined. The intensity of growth and development of juvenile leaves, needles and of the shoot was the lowest in plants growing under 12 hour photoperiod conditions. As the length of the photoperiod increased so did the intensity of these processes. Under the 12 hour photoperiod the development of scale leaves, axillary buds and the formation of the terminal bud started earliest. This process reached completion under the 12 hour photoperiod and the bud remained in a state of dormancy. Seedlings growing under the 12 hour photoperiod were characterized by a low level of stimulators, and at the same time by a high level of inhibitors. On the other hand in seedlings grown at 16 and 20 hour photoperiods the content of stimulators was higher and that of inhibitors lower. A high intensity of growth and development processes was correlated with a high level of stimulators while a high level of inhibitors was correlated with a low intensity of these processes.The obtained results suggest the participation of gibberellins and cytokinins in the processes of regulation of the initiation of scale leaves and axillary buds, and the participation of these hormones and of abscisic acid in the regulation of needle elongation.

scholarly journals Effect of white light irradiation on the endogenous growth regulators content in seeds and seedlings of pine (Pinus silvestris L.)

2015 ◽  
Vol 40 (3) ◽  
pp. 431-438 ◽  
Author(s):  
J. Kopcewicz
Keyword(s):  
Abscisic Acid ◽  
Endogenous Growth ◽  
Growth Regulators ◽  
White Light ◽  
Pinus Silvestris ◽  
Pine Seedlings ◽  
Simultaneous Decrease ◽  
Gibberellin Content ◽  
Seeds Germination ◽  
Effect Of Light

The increase of gibberellin content and decrease of amount of inhibitors in light irradiated pine seedlings were found. It was also stated that stimulating effect of light on pine seeds germination is correlated with the increase of gibberellin and simultaneous decrease of the inhibitor content. The inhibitor isolated from pine seeds proved to be a compound similar in some properties to abscisic acid.

scholarly journals Phytochrome Regulation of Photosynthate Partitioning in Watermelon Plants Exposed to End-of-day Light Treatments

HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 491A-491
Author(s):  
N.K. Damayanthi Ranwala ◽  
D.R. Decoteau ◽  
R.T. Fernandez
Keyword(s):  
Growth And Development ◽  
Dry Weight ◽  
Specific Weight ◽  
Light Period ◽  
Weight Basis ◽  
Photosynthate Partitioning ◽  
Low Intensity ◽  
Petiole Elongation ◽  
Development Processes ◽  
Growth Change

End-of-day (EOD) light treatments were used to study phytochrome involvement in photosynthesis and photosynthate partitioning in watermelon plants. Two-week-old plants were treated with brief low-intensity red (R) or far-red (FR) light for 9 days at the end of daily light period. Petiole elongation in the first two leaves was the first significant growth change in FR-treated plants compared to other plants after 3 days of treatments. This petiole elongation was accompanied by significantly higher photosynthate partitioning to petioles, even without increase in above-ground dry weight of plants. Net CO2 assimilation rate in the second leaf was significantly higher in FR treated plants on a weight basis after 3 days of treatments. Far-red-treated plants had lower chlorophyll content per leaf area and higher stem specific weight compared to R-treated plants after 3 and 6 days of treatments, respectively. Transpiration and stomatal conduction were higher in FR-treated plants compared to other treatments after 3 days of treatments. The EOD FR regulated growth and photosynthate partitioning patterns were reversible when FR treated plants were immediately followed by R. This implies EOD R: FR ratio acting through the phytochrome regulates the growth and development processes in watermelon plants.

scholarly journals Overview of the Genetic Diversity of African Macrotermes (Termitidae: Macrotermitinae) and Implications for Taxonomy, Ecology and Food Science

Insects ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 518
Author(s):  
Bronwyn Egan ◽  
Zwannda Nethavhani ◽  
Barbara van Asch
Keyword(s):  
Negative Impact ◽  
Phylogenetic Reconstruction ◽  
Morphological Characters ◽  
Food Science ◽  
Cryptic Diversity ◽  
African Species ◽  
Genetic Groups ◽  
Wide Range ◽  
Coi Sequences ◽  
High Level

Macrotermes termites play important ecological roles and are consumed by many communities as a delicacy and dietary complement throughout Africa. However, lack of reliable morphological characters has hampered studies of Macrotermes diversity in a wide range of scientific fields including ecology, phylogenetics and food science. In order to place our preliminary assessment of the diversity of Macrotermes in South Africa in context, we analysed a comprehensive dataset of COI sequences for African species including new and publicly available data. Phylogenetic reconstruction and estimates of genetic divergence showed a high level of incongruity between species names and genetic groups, as well as several instances of cryptic diversity. We identified three main clades and 17 genetic groups in the dataset. We propose that this structure be used as a background for future surveys of Macrotermes diversity in Africa, thus mitigating the negative impact of the present taxonomic uncertainties in the genus. The new specimens collected in Limpopo fell into four distinct genetic groups, suggesting that the region harbours remarkable Macrotermes diversity relative to other African regions surveyed in previous studies. This work shows that African Macrotermes have been understudied across the continent, and that the genus contains cryptic diversity undetectable by classic taxonomy. Furthermore, these results may inform future taxonomic revisions in Macrotermes, thus contributing to advances in termitology.

scholarly journals A Screen for Genes That Function in Abscisic Acid Signaling in Arabidopsis thaliana

Genetics ◽  
2002 ◽  
Vol 161 (3) ◽  
pp. 1247-1255 ◽  
Author(s):  
Eiji Nambara ◽  
Masaharu Suzuki ◽  
Suzanne Abrams ◽  
Donald R McCarty ◽  
Yuji Kamiya ◽  
...  
Keyword(s):  
Abscisic Acid ◽  
Growth And Development ◽  
Plant Hormone ◽  
The Other ◽  
Aba Signaling ◽  
Wild Type ◽  
Plant Growth And Development ◽  
Diverse Range ◽  
Abscisic Acid Signaling ◽  
Aba Insensitive

Abstract The plant hormone abscisic acid (ABA) controls many aspects of plant growth and development under a diverse range of environmental conditions. To identify genes functioning in ABA signaling, we have carried out a screen for mutants that takes advantage of the ability of wild-type Arabidopsis seeds to respond to (−)-(R)-ABA, an enantiomer of the natural (+)-(S)-ABA. The premise of the screen was to identify mutations that preferentially alter their germination response in the presence of one stereoisomer vs. the other. Twenty-six mutants were identified and genetic analysis on 23 lines defines two new loci, designated CHOTTO1 and CHOTTO2, and a collection of new mutant alleles of the ABA-insensitive genes, ABI3, ABI4, and ABI5. The abi5 alleles are less sensitive to (+)-ABA than to (−)-ABA. In contrast, the abi3 alleles exhibit a variety of differences in response to the ABA isomers. Genetic and molecular analysis of these alleles suggests that the ABI3 transcription factor may perceive multiple ABA signals.

scholarly journals Incorporation of dl-[2−14C]mevalonic acid lactone into β-carotene and the phytol side chain of chlorophyll in cotyledons of four species of pine seedlings

1967 ◽  
Vol 105 (1) ◽  
pp. 89-92 ◽  
Author(s):  
S. Wieckowski ◽  
T W Goodwin
Keyword(s):  
Mevalonic Acid ◽  
Side Chain ◽  
Pinus Silvestris ◽  
Pine Seedlings ◽  
Acid Lactone ◽  
Β Carotene

1. The incorporation of dl-[2−14C]mevalonic acid lactone into β-carotene and the phytol side chain of chlorophyll has been investigated in cotyledons of four species of pine seedlings (Pinus silvestris, P. contorta, P. radiata and P. jeffrei) grown in darkness and in light. 2. The relative incorporation of label into β-carotene and the phytol side chain of chlorophyll is similar to that observed in experiments on monocotyledons and dicotyledons. 3. The relative incorporation of 14CO2 into β-carotene and phytol is much higher than the incorporation of [2−14C]mevalonic acid.

scholarly journals Desarrollo de Sistema Portable para al Medición del Gasto Energético

2019 ◽  
Author(s):  
David Alexander Urrego-Higuita
Keyword(s):  
Heart Rate ◽  
Energy Consumption ◽  
Gas Sensors ◽  
Indirect Calorimetry ◽  
Growth And Development ◽  
Living System ◽  
Human Being ◽  
Research Paradigm ◽  
Calibration Protocol ◽  
Development Processes

Every living system consumes energy for its growth and development processes, in the human being it becomes a research paradigm, where the aim is to determine the interaction of man with his environment and the transformation of the energy coming from food.For your study there are different techniques which differ in their level of specialization, cost and accuracy, these are divided into predictive, estimating and measurement. For this project a system that seeks to determine the energy consumption during different states is developed, due to the variability of conditions in which the study of energy consumption is developed, different techniques are established such as indirect calorimetry and the conditions for the evaluation by means of accelerometers and the study of heart rate, where a record of the related variables is made through a computational applicationFinally, the behavior of the prototype in different resting states is evaluated, as well as the evaluation of the sensors used in indirect calorimetry, where evaluation tests of the gas sensors and calibration protocol for the flow sensor are defined.

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