scholarly journals Mutations in the tomato gibberellin receptors suppress xylem proliferation and reduce water loss under water-deficit conditions

2020 ◽  
Vol 71 (12) ◽  
pp. 3603-3612 ◽  
Author(s):  
Natanella Illouz-Eliaz ◽  
Idan Nissan ◽  
Ido Nir ◽  
Uria Ramon ◽  
Hagai Shohat ◽  
...  
Keyword(s):  
Water Deficit ◽  
Water Status ◽  
Stomatal Closure ◽  
Normal Growth ◽  
Hydraulic Conductance ◽  
Xylem Vessel ◽  
Leaf Water Content ◽  
Whole Plant ◽  
Drought Conditions ◽  
Better Than

Abstract Low gibberellin (GA) activity in tomato (Solanum lycopersicum) inhibits leaf expansion and reduces stomatal conductance. This leads to lower transpiration and improved water status under transient drought conditions. Tomato has three GIBBERELLIN-INSENSITIVE DWARF1 (GID1) GA receptors with overlapping activities and high redundancy. We tested whether mutation in a single GID1 reduces transpiration without affecting growth and productivity. CRISPR-Cas9 gid1 mutants were able to maintain higher leaf water content under water-deficit conditions. Moreover, while gid1a exhibited normal growth, it showed reduced whole-plant transpiration and better recovery from dehydration. Mutation in GID1a inhibited xylem vessel proliferation, which led to lower hydraulic conductance. In stronger GA mutants, we also found reduced xylem vessel expansion. These results suggest that low GA activity affects transpiration by multiple mechanisms: it reduces leaf area, promotes stomatal closure, and reduces xylem proliferation and expansion, and as a result, xylem hydraulic conductance. We further examined if gid1a performs better than the control M82 in the field. Under these conditions, the high redundancy of GID1s was lost and gid1a plants were semi-dwarf, but their productivity was not affected. Although gid1a did not perform better under drought conditions in the field, it exhibited a higher harvest index.

scholarly journals Mutations in the tomato gibberellin receptors suppresses xylem proliferation and reduces water loss under water-deficit conditions

2020 ◽  
Author(s):  
Natanella Illouz-Eliaz ◽  
Idan Nissan ◽  
Ido Nir ◽  
Uria Ramon ◽  
Hagai Shohat ◽  
...  
Keyword(s):  
Water Deficit ◽  
Water Loss ◽  
Water Status ◽  
Stomatal Closure ◽  
Normal Growth ◽  
Hydraulic Conductance ◽  
Leaf Water Content ◽  
Whole Plant ◽  
Drought Conditions ◽  
Gibberellin Activity

AbstractLow gibberellin (GA) activity in tomato (Solanum lycopersicum) inhibits leaf expansion and reduces stomatal conductance. These lead to lower transpiration and improve water status under transient drought conditions. Tomato has three GIBBERELLIN-INSENSITIVE DWARF1 (GID1) GA receptors with overlapping activities and high redundancy. We have tested whether mutation in a single GID1 reduces transpiration without affecting growth and productivity. CRISPR-Cas9 gid1 mutants were able to maintain higher leaf water content under water-deficit conditions. Moreover, while gid1a exhibited normal growth, it showed reduced whole plant transpiration and better recovery from dehydration. Mutation in GID1a inhibited xylem vessels proliferation that led to lower hydraulic conductance. In stronger GA mutants, we also found reduced xylem vessel expansion. These results suggest that low GA activity affects transpiration by multiple mechanisms; it reduces leaf area, promotes stomatal closure and reduces xylem proliferation and expansion and as a result, xylem hydraulic conductance. We further examined if gid1a perform better than the control M82 in the field. Under these conditions, the high redundancy of GID1s was lost and gid1a plants were semi-dwarf, but their productivity was not affected. Although gid1a did not perform better under drought conditions in the field, it exhibited higher harvest index.HighlightThe loss of the tomato gibberellin receptors GID1s reduced xylem proliferation and xylem hydraulic conductance. These contribute to the effect of low gibberellin activity on water loss under water-deficit condition.

scholarly journals Influence of Water Stress on Grapevines Growing in the Field: From Leaf to Whole-Plant Response

1993 ◽  
Vol 20 (2) ◽  
pp. 143 ◽  
Author(s):  
T Winkel ◽  
S Rambal
Keyword(s):  
Water Stress ◽  
Leaf Area ◽  
Water Status ◽  
Stomatal Closure ◽  
Indirect Evidence ◽  
Hydraulic Conductance ◽  
Water Vapour Pressure ◽  
Vitis Vinifera L ◽  
Plant Water ◽  
Whole Plant

A comparative study of soil-plant water relations was conducted on three grapevine cultivars (Vitis vinifera L. cvv. carignane, merlot, shiraz) to investigate their adjustment to short-term and long-term water stress under field conditions. Adjustment was a function of the relative stability of the internal plant water status on diurnal and seasonal scales. On a diurnal scale, stomatal closure in response to water vapour pressure directly contributed to this stability. Indirect evidence suggested an influence of the soil water status on the diurnal stomatal activity. On a seasonal scale, sufficient leaf hydration required high whole-plant hydraulic conductance. This was achieved by either daily stomatal regulation or limitation of leaf area. Physiological adjustment to water stress through stomatal control was well developed in cv. carignane, which originated in a Mediterranean environment. However, cv. shiraz, which was of mesic origin, apparently adjusted to water stress by reducing leaf area. Our study demonstrates the utility of integrating data on stomatal conductance, leaf water potential and whole-plant hydraulic conductance to interpret whole plant adaptation to water stress, and elucidates two mechanisms by which genotypes differentially acclimate to water stress.

scholarly journals Growth and Water Status of Pruned and Unpruned Woody Landscape Plants Treated with Sumagic (Uniconazole), Cutless (Flurprimidol), or Atrimmec (Dikegulac)

1991 ◽  
Vol 9 (4) ◽  
pp. 231-235
Author(s):  
Jeffrey G. Norcini
Keyword(s):  
Growth Rate ◽  
Water Status ◽  
Stomatal Closure ◽  
Normal Growth ◽  
Leaf Water Content ◽  
Plant Water ◽  
Stem Water Potential ◽  
Euonymus Fortunei ◽  
Application Date ◽  
Stem Water

Abstract Efficacy of Cutless (flurprimidol), Sumagic (uniconazole), and Atrimmec (dikegulac) as affected by application date after pruning was investigated with Pyracantha × ‘Teton’, Ligustrum × vicaryi, and Euonymus fortunei var. coloratus. Cutless (flurprimidol) applied to the medium surface, or foliar sprays of Sumagic (uniconazole) or Atrimmec (dikegulac) were applied 1, 2, 3 or 7 days after pruning (DAP) and to unpruned plants in spring 1989. Height and width were recorded weekly into November, 1989. The effect of these plant growth regulators (PGRs) on short-term plant water relations was measured at 2, 3, 18, 22, or 24 days on unpruned plants and plants treated 2 DAP. Growth rate of Pyracantha was reduced for 6 to 7 weeks if Sumagic (uniconazole) was applied 2 DAP or less, or to unpruned plants; otherwise growth rate was reduced 4 to 5 weeks. Sumagic (uniconazole) reduced Pyracantha growth rate more than Atrimmec (dikegulac); however, Atrimmec-treated plants had a more normal growth habit by the end of the experiment. Atrimmec (dikegulac) also suppressed Ligustrum growth without detrimentally affecting plant appearance. Cutless (flurprimidol) was the only PGR that effectively inhibited growth of Euonymus; however, this treatment excessively dwarfed Pyracantha and Ligustrum. The influence of Atrimmec (dikegulac) and Cutless (flurprimidol) on leaf area varied with the species, and pruning had no effect. Short-ternl effects of Sumagic (uniconazole), Cutless (flurprimidol), and Atrimmec (dikegulac) on transpiration and stomatal conductance to water vapor were species dependent, with some species exhibiting partial stomatal closure. Improvement of plant water status (stem water potential and relative leaf water content) occurred in some cases.

scholarly journals Remotely Sensed Water Limitation in Vegetation: Insights from an Experiment with Unmanned Aerial Vehicles (UAVs)

2019 ◽  
Vol 11 (16) ◽  
pp. 1853 ◽  
Author(s):  
Kelly Easterday ◽  
Chippie Kislik ◽  
Todd Dawson ◽  
Sean Hogan ◽  
Maggi Kelly
Keyword(s):  
Unmanned Aerial Vehicles ◽  
Water Content ◽  
Water Deficit ◽  
Water Status ◽  
Field Measurements ◽  
Leaf Water Content ◽  
Multispectral Imagery ◽  
Spectral Indices ◽  
Aerial Vehicles ◽  
The Relationship

Unmanned aerial vehicles (UAVs) equipped with multispectral sensors present an opportunity to monitor vegetation with on-demand high spatial and temporal resolution. In this study we use multispectral imagery from quadcopter UAVs to monitor the progression of a water manipulation experiment on a common shrub, Baccharis pilularis (coyote brush) at the Blue Oak Ranch Reserve (BORR) ~20 km east of San Jose, California. We recorded multispectral imagery at several altitudes with nearly hourly intervals to explore the relationship between two common spectral indices, NDVI (normalized difference vegetation index) and NDRE (normalized difference red edge index), leaf water content and water potential as physiological metrics of plant water status, across a gradient of water deficit. An examination of the spatial and temporal thresholds at which water limitations were most detectable revealed that the best separation between levels of water deficit were at higher resolution (lower flying height), and in the morning (NDVI) and early morning (NDRE). We found that both measures were able to identify moisture deficit across treatments; however, NDVI was better able to distinguish between treatments than NDRE and was more positively correlated with field measurements of leaf water content. Finally, we explored how relationships between spectral indices and water status changed when the imagery was scaled to courser resolutions provided by satellite-based imagery (PlanetScope).We found that PlanetScope data was able to capture the overall trend in treatments but unable to capture subtle changes in water content. These kinds of experiments that evaluate the relationship between direct field measurements and UAV camera sensitivity are needed to enable translation of field-based physiology measurements to landscape or regional scales.

Anatomical adaptations of Astragalus gombiformis Pomel. under drought stress

2014 ◽  
Vol 9 (12) ◽  
pp. 1215-1225 ◽  
Author(s):  
Fayçal Boughalleb ◽  
Raoudha Abdellaoui ◽  
Nabil Ben-Brahim ◽  
Mohammed Neffati
Keyword(s):  
Water Deficit ◽  
Cross Section ◽  
Wall Thickness ◽  
Vascular Tissue ◽  
Xylem Vessel ◽  
Stomata Density ◽  
Stomata Size ◽  
Severe Water Deficit ◽  
Drought Conditions ◽  
Anatomical Adaptations

AbstractThe present study was designed to study the effect of drought on root, stem and leaf anatomy of Astragalus gombiformis Pomel. Several root, stem and leaf anatomical parameters (cross section diameter, cortex, root cortical cells, pith, leaf lamina and mesophyll thickness) were reduced under moderate to severe water deficit (20–30 days of withheld irrigation). The stele/cross section root ratio increased under moderate water deficit. The root’s and stems vascular systems showed reduced xylem vessel diameter and increased wall thickness under water deficit. In addition, the root xylem vessel density was increased in these drought conditions while it was unchanged in the stems. The stomata density was increased under prolonged drought conditions whereas the stomata size was untouched. The leaf vascular system showed reduced xylem and phloem tissue thickness in the main vein under moderate to severe water deficit. However, in the lamina the vascular tissue and the distance between vascular bundle were unaffected. Our findings suggest a complex network of anatomical adaptations such as a reduced vessel size with increased wall thickness, lesser cortical and mesophyll parenchyma formation and increased stomata density. These proprieties are required for the maintenance of water potential and energy storage under water stress which can improve the resistance of A. gombiformis to survive in arid areas.

scholarly journals Changes of leaf anatomical profile of cocoa clones seedlings in response to drought.

2019 ◽  
Vol 35 (3) ◽  
pp. 177-185
Author(s):  
Fakhrusy Zakariyya ◽  
Didik Indradewa ◽  
Teguh Iman Santoso
Keyword(s):  
Water Content ◽  
Stomatal Density ◽  
Water Status ◽  
Block Design ◽  
Stomatal Closure ◽  
Leaf Tissue ◽  
Leaf Water Content ◽  
Time Interval ◽  
Abaxial Epidermis ◽  
Leaf Mesophyll

Cocoa is a plant that is very sensitive to drought during its growth and development phase, which causes changes up to the anatomical and morphologicallevel. This research is aimed to examine the changes on several leaf anatomical characteristics of three cocoa clones under the drought stress. This research was conducted in a greenhouse of Indonesian Coffee and Cocoa Research Institute, Jember, East Java, Indonesia in January – December 2017. The research was designedusing randomized complete block design with two factors including clones and watering time interval, with three replications. The clone factor comprised of ICS 60,KW 641, and Sulawesi 1. The result showed that the clones of Sulawesi 1 and KW 641 cocoa had a higher mesophyll thickness, lower stomatal density, narrowerstomatal opening, thicker abaxial and adaxial epidermis, and higher relative water content compared to ICS 60 clone. The 8-day watering interval caused a decreasein mesophyll thickness, leaf thickness, increase in stomatal density, stomatal closure, decrease in abaxial epidermis thickness, and decrease in water status within the plant tissue. The thicker the leaf mesophyll tissue, the higher the leaf water content was. This showed that the water status within a plant leaf tissue determined bythe leaf mesophyll thickness.

scholarly journals MORPHOLOGICAL CHARACTERISTICS AND WATER STATUS OF SOME TUNISIAN BARLEY GENOTYPES SUBMITTED TO WATER STRESS

2015 ◽  
Vol 3 (5) ◽  
pp. 60-76
Author(s):  
Mansouri ◽  
Radhouane
Keyword(s):  
Climate Change ◽  
Water Stress ◽  
Water Deficit ◽  
Water Status ◽  
Morphological Characteristics ◽  
Leaf Water ◽  
Growth And Yield ◽  
Annual Rainfall ◽  
Leaf Water Content ◽  
Barley Genotypes

Tunisia has been qualified as a country vulnerable to climate change that will be unregistered a great drop of annual rainfall and an increase of evaporation.  Response strategies of agriculture to drought will be critical because drought is one of the major abiotic stresses which adversely affect crop growth and yield. Among strategies to be developed to cope with the effect of climate change, recourse of genetic diversity and new varietal creation can be a solution among other methods. In this study, four barley genotypes were cultivated in semi-controlled conditions and submitted to three levels of water stress.  Data were recorded on number of grain per plant (NGP), one thousand grains weight (PMG), total leaf surface (TLS), plant height (HAT), stomata density (DS), leaf water content (RWC) and leaf water potential (LWP). Results showed that morphological characteristics (HAT, TLS, DS), yield components (NGP, PMG) and water status (LWP, RWC) of barley genotypes were decreased significantly. However, moderate water deficit didn’t affect significantly the most of parameters studied. Study had demonstrated also that barley genotypes developed different strategies and mechanisms to cope with water deficit, based essentially on their osmotic adjustment capacity.

Medicago truncatula response to water-deficit stress: whole plant perspectives

2021 ◽  
Author(s):  
◽  
Verónica Castañeda Presa
Keyword(s):  
Water Deficit ◽  
Medicago Truncatula ◽  
Water Status ◽  
Water Deficit Stress ◽  
World Population ◽  
Fibrous Root ◽  
Model Plant ◽  
Whole Plant ◽  
Plant Level

Medicago truncatula is a forage legume with agricultural but also scientifical interest, being used as a model plant for the study of legumes’ biology. Within a climate change context, it is of great importance to maintain/increase plant yield in stressful growth conditions to meet the requirements of the increasing world population. In order to achieve this, it is mandatory to further understand the adaptive response of plants to water-deficit stress, for which the use of this model plant results of great utility. In the present study, the simultaneous study of various plant organs with particular focus on the root system allows us a more integrative understanding of water-deficit response mechanisms from a whole-plant perspective. The root tissue was studied in Chapter 1, distinguishing between the thick taproot and the much thinner fibrous root. The different behaviour of both root types under well-watered as well as under water-deficit conditions was studied from a physiological and metabolic perspec-tive. This study highlighted the active role of the taproot rather than being considered a mere nutrient storage organ. The taproot showed a more resilient nature towards water-deficit stress than the fibrous root, while sucrose cleavage modulation, together with proline metabolism sug-gested a crucial role of these pathways in the root adaptation to water-deficit stress. In Chapter 2 we aimed to address different water-deficit conditions that can affect plant water status, using iso-osmotical conditions of salinity (NaCl and KCl), lack of irrigation and an osmoticum (PEG). This approach allows us to identify the similarities and differences in the mechanisms involved in the response to each stress at the whole-plant level. While PEG was dismissed as a reliable drought-stress mimicker, NaCl and KCl led to similar responses, with a slightly higher negative effect of KCl on plant metabolism. On the other hand, an emphasis on the shoot and root protection was observed for NaCl and no-irrigation stress, respectively. The study of the phloem sap allowed us to better understand the responses to the different water-deficit conditions at a whole-plant level. In summary, this study provides further insight into the response at the whole-plant level of M. truncatula to water-deficit conditions from a biochemical, metabolic and physiological point of view.

scholarly journals Overexpression of MdATG8i improves water use efficiency in transgenic apple by modulating photosynthesis, osmotic balance, and autophagic activity under moderate water deficit

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Xin Jia ◽  
Ke Mao ◽  
Ping Wang ◽  
Yu Wang ◽  
Xumei Jia ◽  
...  
Keyword(s):  
Water Use Efficiency ◽  
Water Deficit ◽  
Water Use ◽  
Photosynthetic Capacity ◽  
Critical Role ◽  
Drought Conditions ◽  
Moderate Drought ◽  
Use Efficiency ◽  
Autophagic Activity

AbstractWater deficit is one of the major limiting factors for apple (Malus domestica) production on the Loess Plateau, a major apple cultivation area in China. The identification of genes related to the regulation of water use efficiency (WUE) is a crucial aspect of crop breeding programs. As a conserved degradation and recycling mechanism in eukaryotes, autophagy has been reported to participate in various stress responses. However, the relationship between autophagy and WUE regulation has not been explored. We have shown that a crucial autophagy protein in apple, MdATG8i, plays a role in improving salt tolerance. Here, we explored its biological function in response to long-term moderate drought stress. The results showed that MdATG8i-overexpressing (MdATG8i-OE) apple plants exhibited higher WUE than wild-type (WT) plants under long-term moderate drought conditions. Plant WUE can be increased by improving photosynthetic efficiency. Osmoregulation plays a critical role in plant stress resistance and adaptation. Under long-term drought conditions, the photosynthetic capacity and accumulation of sugar and amino acids were higher in MdATG8i-OE plants than in WT plants. The increased photosynthetic capacity in the OE plants could be attributed to their ability to maintain optimal stomatal aperture, organized chloroplasts, and strong antioxidant activity. MdATG8i overexpression also promoted autophagic activity, which was likely related to the changes described above. In summary, our results demonstrate that MdATG8i-OE apple lines exhibited higher WUE than WT under long-term moderate drought conditions because they maintained robust photosynthesis, effective osmotic adjustment processes, and strong autophagic activity.

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