Component traits of plant water use are modulated by vapour pressure deficit in pearl millet (Pennisetum glaucum (L.) R.Br.)

Traits influencing plant water use eventually define the fitness of genotypes for specific rainfall environments. We assessed the response of several water use traits to vapour pressure deficit (VPD) in pearl millet (Pennisetum glaucum (L.) R.Br.) genotypes known to differ in drought adaptation mechanisms: PRLT 2/89–33 (terminal drought-adapted parent), H 77/833–2 (terminal drought-sensitive parent) and four near-isogenic lines introgressed with a terminal drought tolerance quantitative trait locus (QTL) from PRLT 2/89–33 (ICMR01029, ICMR01031, ICMR02042, and ICMR02044). Plant water use traits at various levels of plant organisation were evaluated in seven experiments in plants exposed either transiently or over the long term to different VPD regimes: biomass components, transpiration (water usage per time unit) and transpiration rate (TR) upon transient VPD increase (g H2O cm–2 h–1)), transpiration efficiency (g dry biomass per kg H2O transpired), leaf expansion rate (cm per thermal time unit) and root anatomy (endodermis dimensions)). High VPD decreased biomass accumulation by reducing tillering, the leaf expansion rate and the duration of leaf expansion; decreased root endodermis cell size; and increased TR and the rate of TR increase upon gradual short-term VPD increases. Such changes may allow plants to increase their water transport capacity in a high VPD environment and are genotype-specific. Some variation in water use components was associated with terminal drought adaptation QTL. Knowledge of water use traits’ plasticity in growth environments that varied in evaporative demand, and on their genetic determinacy, is necessary to develop trait-based breeding approaches to complex constraints.

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Terminal drought-tolerant pearl millet [Pennisetum glaucum (L.) R. Br.] have high leaf ABA and limit transpiration at high vapour pressure deficit

Journal of Experimental Botany ◽

10.1093/jxb/erq013 ◽

2010 ◽

Vol 61 (5) ◽

pp. 1431-1440 ◽

Cited By ~ 144

Author(s):

Jana Kholová ◽

C. T. Hash ◽

P. Lava Kumar ◽

Rattan S. Yadav ◽

Marie Kočová ◽

...

Keyword(s):

Pearl Millet ◽

Vapour Pressure ◽

Pennisetum Glaucum ◽

Vapour Pressure Deficit ◽

Terminal Drought ◽

Drought Tolerant ◽

High Vapour Pressure

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Influence of Climatic Variables on Whole-plant Water use of Cocoa under Limited Soil Moisture Condition

Journal of Agriculture and Ecology Research International ◽

10.9734/jaeri/2019/v19i430092 ◽

2019 ◽

pp. 1-8

Author(s):

Femi S. Omotayo ◽

Philip G. Oguntunde ◽

Ayorinde A. Olufayo

Keyword(s):

Soil Moisture ◽

Relative Humidity ◽

Solar Radiation ◽

Correlation Coefficient ◽

Water Use ◽

Vapour Pressure ◽

Plant Water ◽

Plant Water Use ◽

Whole Plant ◽

Cocoa Plantation

Cocoa (Theobroma cacao L.) is a cash crop that is cultivated in many tropical regions of the world and is highly productive under favourable climatic conditions. Cocao, being originally an under storey tree of rainforests in tropical America, is traditionally cultivated below the canopy of shade trees. This study is carried out to establish the influence of climatic variables on whole-plant water use of cocoa under limited soil moisture conditions. An experimental plot was made in an even – aged 54 years old cocoa plantation which was demarcated while Water use measurement carried out for 20 consecutive days at the center of the cocoa plantation field at the Federal University of Technology, Akure using the temperature difference method (Sap flow meter). The results of evaporation rate and water consumed by crops led to decrease in soil water in the monitored root zone from 0.049 to 0.015 m3 m-3. Solar radiation reached a high value of 1002.37 Wm-2, with day time average of 238.02 Wm-2. Temperature ranges between 16.41 and 34.19ºC with a daily average of about 24.39ºC. Relative humidity varied from 98.60% to less than 32.37% with daily mean of around 74.90%. Vapour pressure varied from 0.01 to 2.87 kpa. The day time wind speeds rarely exceed 5.2 ms-1 while the daily averages were generally around 1.09 ms-1. The results also show that transpiration, (Ec) is mostly influenced by solar radiation with a correlation coefficient of 0.71 while other variable like temperature, Vapour pressure deficit, and Relative humidity has correlation coefficient of 0.62, 0.50 and 0.58 respectively. The total amount of rainfall during the experiment was 38.9 mm. This shows that solar radiation has greater influence on the transpiration of the cocoa plant than other variables in the study area.

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Aquaporins are main contributors of root hydraulic conductivity in pearl millet [Pennisetum glaucum (L) R. Br.]

10.1101/2020.05.13.094094 ◽

2020 ◽

Author(s):

Alexandre Grondin ◽

Pablo Affortit ◽

Christine Tranchant-Dubreuil ◽

Carla de la Fuente Cantó ◽

Cédric Mariac ◽

...

Keyword(s):

Hydraulic Conductivity ◽

Water Use Efficiency ◽

Water Transport ◽

Pearl Millet ◽

Water Use ◽

Pennisetum Glaucum ◽

Root Hydraulic Conductivity ◽

Plant Water Use ◽

Whole Plant ◽

Use Efficiency

AbstractPearl millet is a key cereal for food security in arid and semi-arid regions but its yield is increasingly threatened by water stress. Physiological mechanisms consisting in saving water or increasing water use efficiency can alleviate that stress. Aquaporins (AQP) are water channels contributing to plant hydraulic balance that are supposedly involved in these mechanisms by mediating root water transport. However, AQP remain largely uncharacterized in pearl millet. Here, we studied AQP function in root water transport in two pearl millet lines contrasting for water use efficiency (WUE). We observed that these lines were also contrasting for root hydraulic conductivity (Lpr) and AQP contribution to Lpr, the line with lower WUE showing significantly higher AQP contribution to Lpr. To investigate the AQP isoforms contributing to Lpr, we developed genomic approaches to first identify the entire AQP family in pearl millet and second study the plasma membrane intrinsic proteins (PIP) gene expression profile. We identified and annotated 33 AQP genes in pearl millet among which ten encoded PIP isoforms. PgPIP1-3 and PgPIP1-4 were significantly more expressed in the line showing lower WUE, higher Lpr and higher AQP contribution to Lpr. Overall, our study suggests that AQP from the PIP1 family are the main contributor of Lpr in pearl millet and are possibly associated to whole plant water use mechanisms. This study paves the way for further investigations on AQP functions in pearl millet hydraulics and adaptation to environmental stresses.The newly sequenced nucleotide sequences reported in this article have been submitted to GenBank under the submission number 2333840 (TPA grp467567). Assignment of GenBank accession number is in process.

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Tolerance of combined drought and heat stress is associated with transpiration maintenance and water soluble carbohydrates in wheat grains

10.1101/2020.05.08.085118 ◽

2020 ◽

Author(s):

Abdeljalil El Habti ◽

Delphine Fleury ◽

Nathaniel Jewell ◽

Trevor Garnett ◽

Penny J. Tricker

Keyword(s):

Heat Stress ◽

Water Use ◽

Vapour Pressure Deficit ◽

Water Soluble ◽

Soluble Carbohydrates ◽

Plant Water ◽

Plant Water Use ◽

Whole Plant ◽

Water Soluble Carbohydrates ◽

Drought And Heat Stress

AbstractWheat (Triticum aestivum L.) production is increasingly challenged by simultaneous drought and heatwaves. We assessed the effect of both stresses combined on whole plant water use and carbohydrate partitioning in eight bread wheat genotypes that showed contrasting tolerance. Plant water use was monitored throughout growth, and water-soluble carbohydrates (WSC) and starch were measured following a three-day heat treatment during drought. WSC were predominantly allocated to the spike in modern Australian varieties, whereas the stem contained most WSC in older genotypes. Combined drought and heat stress increased WSC partitioning to the spike in older genotypes but not in the modern varieties. Glucose and fructose concentrations in grains measured 12 days after anthesis were associated with final grain weight in the main spike. At the whole plant level, combined drought and heat stress differentially altered daily water use and transpiration response to vapour pressure deficit during grain filling, compared to drought only. Final grain yield was increasingly associated with aboveground biomass and total water use with increasing stress intensity. Ability to maintain transpiration, especially following combined drought and heat stress, appears essential for maintaining wheat productivity.One sentence summaryHigher yield following drought and heat stress in wheats that maintain transpiration and have higher water-soluble carbohydrates content in grains.

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