High temperature and water deficit may reduce seed number in field pea purely by decreasing plant growth rate

2003 ◽  
Vol 30 (11) ◽  
pp. 1151 ◽  
Author(s):  
Lydie Guilioni ◽  
Jacques Wéry ◽  
Jérémie Lecoeur
Keyword(s):  
Growth Rate ◽  
Plant Growth ◽  
Water Deficit ◽  
Water Status ◽  
Reproductive Organs ◽  
Yield Component ◽  
Field Pea ◽  
Dependent Manner ◽  
Seed Number ◽  
Variable Yield

Seed number, the most variable yield component of legumes is strongly affected by heat stress (HS) and water deficit (WD). The objective of this paper is to investigate whether HS and WD reduced seed number in field pea through their negative effects on biomass production rather than by specific effects on the developing reproductive organs. Several field and glasshouse experiments were carried out in southern France, in which HS and / or WD of various intensities, durations and positions in the plant lifecycle were imposed on several pea cultivars. WD and HS reduced seed number, in an intensity-dependent manner. They also changed the distribution of seeds along the stem. Plants subjected to WD and mild HS had more seeds on the basal phytomers than did control plants, making it possible to exclude direct effects of stress on seed development. In contrast, severe HS resulted in the immediate abortion of reproductive organs. WD and HS also decreased net photosynthesis (Pn), but only during the period of constraint. Quantitative relationships between Pn and soil water status and between Pn and leaf temperature were established. Nevertheless, in all cases there was a single linear relationship between final seed number and plant growth rate during the critical period for seed set (from the beginning of flowering to the beginning of seed fill for the last seed-bearing phytomer). This reflects the reproductive plasticity of pea, which adjusts the number of reproductive sinks in an apparent balance with assimilate availability in the plant.

Linking physiological and genetic analyses of the control of leaf growth under changing environmental conditions

2005 ◽  
Vol 56 (9) ◽  
pp. 937 ◽  
Author(s):  
François Tardieu ◽  
Matthieu Reymond ◽  
Bertrand Muller ◽  
Christine Granier ◽  
Thierry Simonneau ◽  
...  
Keyword(s):  
Growth Rate ◽  
Water Deficit ◽  
Environmental Conditions ◽  
Leaf Growth ◽  
Water Status ◽  
Recombinant Inbred Lines ◽  
Vapour Pressure Deficit ◽  
Leaf Elongation ◽  
Response Curves ◽  
Division Rate

Decrease in leaf growth rate under water deficit can be seen as an adaptive process. The analysis of its genetic variability is therefore important in the context of drought tolerance. Several mechanisms are widely believed to drive the reduction in leaf growth rate under water deficit, namely leaf carbon balance, incomplete turgor maintenance, and decrease in cell wall plasticity or in cell division rate, with contributions from hormones such as abscisic acid or ethylene. Each of these mechanisms is still controversial, and involves several families of genes. It is argued that gene regulatory networks are not feasible for modelling such complex systems. Leaf growth can be modelled via response curves to environmental conditions, which are considered as ‘meta-mechanisms’ at a higher degree of organisation. Response curves of leaf elongation rate to meristem temperature, atmospheric vapour pressure deficit, and soil water status were established in recombinant inbred lines (RILs) of maize in experiments carried out in the field and in the greenhouse. A quantitative trait locus (QTL) analysis was conducted on the slopes of these responses. Each parameter of the ecophysiological model could then be computed as the sum of QTL effects, allowing calculation of parameters of new RILs, either virtual or existing. Leaf elongation rates of new RILS were simulated and were similar to measurements in a growth chamber experiment. This opens the way to the simulation of virtual genotypes, known only by their alleles, in any climatic scenario. Each genotype is therefore represented by a set of response parameters, valid in a large range of conditions and deduced from the alleles at QTLs.

Plant growth co-ordination in natura: a unique temperature-controlled law among vegetative and reproductive organs in mango

2013 ◽  
Vol 40 (3) ◽  
pp. 280 ◽  
Author(s):  
Anaëlle Dambreville ◽  
Frédéric Normand ◽  
Pierre-Éric Lauri
Keyword(s):  
Growth Rate ◽  
Plant Growth ◽  
Growth Parameters ◽  
Growth Dynamics ◽  
Reproductive Organs ◽  
Effect Of Temperature ◽  
Growth Unit ◽  
Mango Tree ◽  
Temperature Controlled ◽  
The Impact

The impact of temperature on plant growth is usually studied on the leaves of annuals. We studied in natura the effect of temperature on the growth of three plant organs: the growth unit (GU) axis; its attached leaves, considering their position along the axis; and the inflorescence axis. Mango tree was chosen as plant model. Organ growth was measured at different seasons and elevations, permitting a range of temperatures overlapping the optimal range for mango growth. Four growth parameters were investigated: the final organ size, the duration of growth, the maximal absolute growth rate (AGRmax) and the relative growth rate at the time of AGRmax (RGRip). Temporal growth dependencies were found between the axis and its leaves, regardless of their positions. Size dependencies were revealed only between the GU axis and its proximal leaf. Strong effects of temperature on duration of growth and on RGRip were observed regardless of the organ studied. A common allometric coefficient linked duration of growth and RGRip of all organs although the intercepts for axes and leaves were different. These relationships strongly suggested that regardless of the physiological mechanisms subtending the growth dynamics, e.g. auto- vs heterotrophy, a common temperature-controlled allometric constraint is probably underlying the growth of all these organs in mango.

Changes in growth rate and thyroid- and sex-hormones blood levels in rats under sub-chronic lithium treatment

2006 ◽  
Vol 25 (5) ◽  
pp. 243-250 ◽  
Author(s):  
M S Allagui ◽  
N Hfaiedh ◽  
C Vincent ◽  
F Guermazi ◽  
J-C Murat ◽  
...  
Keyword(s):  
Growth Rate ◽  
Lithium Treatment ◽  
Lithium Carbonate ◽  
Serum Levels ◽  
Antagonistic Effect ◽  
Blood Levels ◽  
Vaginal Mucosa ◽  
Dependent Manner ◽  
Serum Concentrations ◽  
Dose Dependent

Lithium therapy, mainly used in curing some psychiatric diseases, is responsible for numerous undesirable side effects. The present study is a contribution to the understanding of the pathophysiological mechanisms underlying lithium toxicity. Male and female mature rats were divided into three batches and fed commercial pellets: one batch was the control and the second and third batches were given 2 g (Li1) and 4 g (Li2) of lithium carbonate/kg of food/day, respectively. After 7, 14, 21 and 28 days, serum levels of free tri-iodothyronine (FT3), thyroxine (FT4), testosterone and estradiol were measured. Attention was also paid to growth rate and a histological examination of testes or vaginal mucosa was carried out. In treated rats, a dose-dependent loss of appetite and a decrease in growth rate were observed, together with symptoms of polydypsia, polyuria and diarrhea. Lithium serum concentrations increased from 0.44 mM (day 7) to 1.34 mM (day 28) in Li1 rats and from 0.66 to 1.45 mM (day 14) in Li2 rats. Li2 treatment induced a high mortality after 14 days, reaching 50-60% in female and male animals. From these data, the LD50 (14 days Li2 chronic treatment) was calculated to be about 0.3 g/day per kilogram of animal, leading to Li serum concentrations of about 1.4 mM. A significant decrease of FT3 and FT4 was observed in treated rats. This effect appeared immediately for the highest dose and was more pronounced for FT3, resulting in an increase of the FT4/FT3 ratio. In males, testosterone decreased and spermatogenesis was stopped. Conversely, in females, estradiol increased in a dose-dependent manner as the animals were blocked in the diestrus phase at day 28. This finding supports a possible antagonistic effect of lithium on the estradiol receptors.

scholarly journals Growth Promotion or Osmotic Stress Response: How SNF1-Related Protein Kinase 2 (SnRK2) Kinases Are Activated and Manage Intracellular Signaling in Plants

Plants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1443
Author(s):  
Yoshiaki Kamiyama ◽  
Sotaro Katagiri ◽  
Taishi Umezawa
Keyword(s):  
Protein Kinase ◽  
Plant Growth ◽  
Osmotic Stress ◽  
Protein Function ◽  
Intracellular Signaling ◽  
Growth Promotion ◽  
Research Field ◽  
Dependent Manner ◽  
Related Protein ◽  
Wide Range

Reversible phosphorylation is a major mechanism for regulating protein function and controls a wide range of cellular functions including responses to external stimuli. The plant-specific SNF1-related protein kinase 2s (SnRK2s) function as central regulators of plant growth and development, as well as tolerance to multiple abiotic stresses. Although the activity of SnRK2s is tightly regulated in a phytohormone abscisic acid (ABA)-dependent manner, recent investigations have revealed that SnRK2s can be activated by group B Raf-like protein kinases independently of ABA. Furthermore, evidence is accumulating that SnRK2s modulate plant growth through regulation of target of rapamycin (TOR) signaling. Here, we summarize recent advances in knowledge of how SnRK2s mediate plant growth and osmotic stress signaling and discuss future challenges in this research field.

Sink strength of citrus rootstocks under water deficit

2021 ◽  
Author(s):  
Simone F da Silva ◽  
Marcela T Miranda ◽  
Vladimir E Costa ◽  
Eduardo C Machado ◽  
Rafael V Ribeiro
Keyword(s):  
Plant Growth ◽  
Root Growth ◽  
Water Deficit ◽  
Carbon Allocation ◽  
Sink Strength ◽  
Rangpur Lime ◽  
Carbon Supply ◽  
Valencia Orange ◽  
Source Sink ◽  
Orange Trees

Abstract Carbon allocation between source and sink organs determines plant growth and is influenced by environmental conditions. Under water deficit, plant growth is inhibited before photosynthesis and shoot growth tends to be more sensitive than root growth. However, the modulation of source-sink relationship by rootstocks remain unsolved in citrus trees under water deficit. Citrus plants grafted on Rangpur lime are drought tolerant, which may be related to a fine coordination of the source-sink relationship for maintaining root growth. Here, we followed 13C allocation and evaluated physiological responses and growth of Valencia orange trees grafted on three citrus rootstocks (Rangpur lime, Swingle citrumelo and Sunki mandarin) under water deficit. As compared to plants on Swingle and Sunki rootstocks, ones grafted on Rangpur lime showed higher stomatal sensitivity to the initial variation of water availability and less accumulation of non-structural carbohydrates in roots under water deficit. High 13C allocation found in Rangpur lime roots indicates this rootstock has high sink demand associated with high root growth under water deficit. Our data suggest that Rangpur lime rootstock used photoassimilates as sources of energy and carbon skeletons for growing under drought, which is likely related to increases in root respiration. Taken together, our data revealed that carbon supply by leaves and delivery to roots are critical for maintaining root growth and improving drought tolerance, with citrus rootstocks showing differential sink strength under water deficit.

scholarly journals Brassinolide Enhances the Level of Brassinosteroids, Protein, Pigments, and Monosaccharides in Wolffia arrhiza Treated with Brassinazole

Plants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1311
Author(s):  
Magdalena Chmur ◽  
Andrzej Bajguz
Keyword(s):  
Plant Growth ◽  
Growth And Development ◽  
Inhibitory Effect ◽  
Dependent Manner ◽  
Plant Growth And Development ◽  
Concentration Dependent Manner ◽  
Spectrophotometric Methods ◽  
Synthetic Inhibitor ◽  
Wolffia Arrhiza ◽  
First Time

Brassinolide (BL) represents brassinosteroids (BRs)—a group of phytohormones that are essential for plant growth and development. Brassinazole (Brz) is as a synthetic inhibitor of BRs’ biosynthesis. In the present study, the responses of Wolffia arrhiza to the treatment with BL, Brz, and the combination of BL with Brz were analyzed. The analysis of BRs and Brz was performed using LC-MS/MS. The photosynthetic pigments (chlorophylls, carotenes, and xanthophylls) levels were determined using HPLC, but protein and monosaccharides level using spectrophotometric methods. The obtained results indicated that BL and Brz influence W. arrhiza cultures in a concentration-dependent manner. The most stimulatory effects on the growth, level of BRs (BL, 24-epibrassinolide, 28-homobrassinolide, 28-norbrassinolide, catasterone, castasterone, 24-epicastasterone, typhasterol, and 6-deoxytyphasterol), and the content of pigments, protein, and monosaccharides, were observed in plants treated with 0.1 µM BL. Whereas the application of 1 µM and 10 µM Brz caused a significant decrease in duckweed weight and level of targeted compounds. Application of BL caused the mitigation of the Brz inhibitory effect and enhanced the BR level in duckweed treated with Brz. The level of BRs was reported for the first time in duckweed treated with BL and/or Brz.

scholarly journals Vegetation Response to Goats Grazing Intensity in Semiarid Hilly Grassland of the Loess Plateau, Lanzhou, China

2021 ◽  
Vol 13 (6) ◽  
pp. 3569
Author(s):  
Hua Cheng ◽  
Baocheng Jin ◽  
Kai Luo ◽  
Jiuying Pei ◽  
Xueli Zhang ◽  
...  
Keyword(s):  
Growth Rate ◽  
Community Structure ◽  
Plant Growth ◽  
Loess Plateau ◽  
Grazing Intensity ◽  
Gps Tracking ◽  
Growth Stages ◽  
The Loess Plateau ◽  
Vegetation Community ◽  
Natural Grasslands

Quantitatively estimating the grazing intensity (GI) effects on vegetation in semiarid hilly grassland of the Loess Plateau can help to develop safe utilization levels for natural grasslands, which is a necessity of maintaining livestock production and sustainable development of grasslands. Normalized difference vegetation index (NDVI), field vegetation data, and 181 days (one goat per day) of GPS tracking were combined to quantify the spatial pattern of GI, and its effects on the vegetation community structure. The spatial distribution of GI was uneven, with a mean value of 0.50 goats/ha, and 95% of the study area had less than 1.30 goats/ha. The areas with utilization rates of rangeland (July) lower than 45% and 20% made up about 95% and 60% of the study area, respectively. Grazing significantly reduced monthly aboveground biomass, but the grazing effects on plant growth rate were complex across the different plant growth stages. Grazing impaired plant growth in general, but the intermediate GI appeared to facilitate plant growth rate at the end of the growing seasons. Grazing had minimal relationship with vegetation community structure characteristics, though Importance Value of forbs increased with increasing GI. Flexibility in the number of goats and conservatively defining utilization rate, according to the inter-annual variation of utilization biomass, would be beneficial to achieve ecologically healthy and economically sustainable GI.

Low temperature acclimation and legacy effects of summer water deficits in olive freezing resistance

2021 ◽  
Author(s):  
Nadia S Arias ◽  
Fabián G Scholz ◽  
Guillermo Goldstein ◽  
Sandra J Bucci
Keyword(s):  
Plant Growth ◽  
Water Deficit ◽  
Low Temperatures ◽  
Cell Damage ◽  
Leaf Water ◽  
Leaf Nitrogen Content ◽  
Legacy Effects ◽  
Freezing Resistance ◽  
Lower Growth ◽  
Water Deficits

Abstract Low temperatures and drought are the main environmental factors affecting plant growth and productivity across most of the terrestrial biomes. The objective of this study was to analyze the effects of water deficits before the onset of low temperatures in winter to enhance freezing resistance in olive trees. The study was carried out near the coast of Chubut, Argentina. Plants of five olive cultivars were grown out-door in pots and exposed to different water deficit treatments. We assessed leaf water relations, ice nucleation temperature (INT), cell damage (LT50), plant growth and leaf nitrogen content during summer and winter in all cultivars and across water deficit treatments. Leaf INT and LT50 decreased significantly from summer to winter within each cultivar and between treatments. We observed a trade-off between resources allocation to freezing resistance and vegetative growth, such that an improvement in resistance to sub-zero temperatures was associated to lower growth in tree height. Water deficit applied during summer increased the amount of osmotically active solutes and decreased the leaf water potentials. This type of legacy effects persists during the winter after the water deficit even when treatment was removed, because of natural rainfalls.

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