Growth and Physiological Responses to Drought Stress in Four Oleander Clones

Oleander (Nerium oleander L.), native to southern Asia and the Mediterranean region, is a fast-growing evergreen shrub planted widely in the southern United States. A greenhouse study was conducted to quantify the growth and physiological responses of two cultivars, Hardy Pink and Hardy Red, and two breeding lines, EP1 and EP2, of oleander to a 12-week cyclic drought stress. Drought stress was imposed by irrigating the plants to near container capacity and then withholding irrigation until predetermined container weights were reached. Compared with the control where plants were well-irrigated throughout the experiment, shoot dry weight (DW) was reduced by 52%, 41%, 34%, and 11% in EP1, EP2, ‘Hardy Red’, and ‘Hardy Pink’, respectively. Root-to-shoot DW ratio was higher for the drought-treated plants than the control, regardless of cultivar or breeding line (hereafter, clone). The increase in root-to-shoot DW ratio from the drought treatment was highest in EP1, followed by EP2, ‘Hardy Pink’, and ‘Hardy Red.’ New shoot growth was greatest in ‘Hardy Pink’, followed by ‘Hardy Red’, EP1, and EP2. The number of newly developed shoots during the drought treatment period was 6.8, 3.0, 0.7, and 0.0 in ‘Hardy Pink’, ‘Hardy Red’, EP1, and EP2, respectively. As substrate volumetric moisture content decreased from 30%, leaf net photosynthetic rate (Pn), evapotranspiration rate (E), and stomatal conductance (gs) decreased in all clones. A curvilinear relationship between Pn and gs was found in all clones. EP1 had a lower maximum Pn (Pm) than those of ‘Hardy Pink’ and EP2 but was not different from that of ‘Hardy Red’. Predawn leaf water potential began to decrease rapidly when substrate moisture content dropped below 15% in all clones. During the dry-down, compared with the control, increases in minimal fluorescence (F0) or decreases in maximal fluorescence (Fm) and Fv/Fm (Fv = Fm – F0) in drought-stressed plants were observed in all clones, indicating some damage in photosystem II from the drought treatment. However, compared with growth parameters, the differences in physiological responses to drought stress among the clones were much smaller. ‘Hardy Pink’ was more tolerant to drought stress than ‘Hardy Red’ and the other two clones in terms of productivity because it maintained greatest growth during the drought-stress period. However, EP2 and EP1 may be more tolerant if survival is concerned because they had a higher root-to-shoot DW ratio with minimal new growth.

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Growth and Physiological Responses of Four Rose Rootstocks to Drought Stress

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.134.2.202 ◽

2009 ◽

Vol 134 (2) ◽

pp. 202-209 ◽

Cited By ~ 13

Author(s):

Genhua Niu ◽

Denise S. Rodriguez

Keyword(s):

Drought Stress ◽

Moisture Content ◽

Leaf Area ◽

Physiological Responses ◽

Growth Parameter ◽

Dry Weight ◽

Drought Treatment ◽

Dry Down ◽

Substrate Moisture ◽

Mild Drought

Drought-tolerant garden roses (Rosa spp.) are needed in arid and semiarid regions where irrigation water is scarce. The vast majority of garden rose cultivars are budded or grafted onto rootstocks and are seldom grown on their own roots. The objective of this study was to compare the growth and physiological responses of four rose rootstocks to drought stress. Rosa ×hybrida ‘Dr. Huey’, R. ×fortuniana, R. multiflora, and R. odorata grown in 12-L containers were well-irrigated throughout the experiment or were subjected to mild drought stress for five or six cycles, depending on rootstocks, over 10 weeks. Following the mild drought stress cycles, plants that received the mild drought treatment were subjected to a severe dry-down before termination of the experiment. In R. ×fortuniana, drought stress did not affect any growth parameter. Compared with the well-irrigated plants, shoot dry weight of ‘Dr. Huey’, R. multiflora, and R. odorata were reduced by 22%, 33%, and 38%, respectively, by the drought treatment. The final leaf area of R. multiflora and R. odorata was reduced by 42% and 59%, respectively, compared with the control plants. The final leaf area of ‘Dr. Huey’ was not influenced by the drought treatment. Root to shoot ratio in ‘Dr. Huey’ was unaffected, while that of R. multiflora and R. odorata increased as a result of the drought treatment. As substrate moisture content decreased, leaf relative water content (RWC) of all rootstocks decreased linearly, with differences in decreasing slope or intercept of the linear regression lines among rootstocks. Predawn leaf water potential during the dry-down began to decrease rapidly when substrate moisture content decreased to below 20% (25% in R. odorata) in ‘Dr. Huey’, R. ×fortuniana, and R. multiflora. Leaf net photosynthetic rate (Pn), transpiration rate (E) and stomatal conductance (gs) of all rootstocks decreased rapidly during the dry-down as substrate moisture content decreased from 25%. In ‘Dr. Huey’ and R. ×fortuniana, Pn, E, and gs were closely correlated with leaf RWC, while E and gs of R. odorata were not. Correlations between gas exchange rates (Pn, E, and gs) and leaf RWC in R. multiflora were weaker than those in ‘Dr. Huey’ and R. ×fortuniana. At low substrate moisture content (below 15%), Pn, E, and gs in R. odorata were lower than those in other rootstocks. Growth reduction was greatest in R. odorata, regardless of the least water deficit of the substrate, followed by R. multiflora and ‘Dr. Huey’. The results of this study suggest that R. ×fortuniana was the most tolerant and R. odorata was the least tolerant to drought stress.

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The Effect of Substrate Moisture Content on Growth and Physiological Responses of Two Landscape Roses (Rosa hybrida L.)

HortScience ◽

10.21273/hortsci.49.6.741 ◽

2014 ◽

Vol 49 (6) ◽

pp. 741-745 ◽

Cited By ~ 3

Author(s):

Xiaoya Cai ◽

Terri Starman ◽

Genhua Niu ◽

Charles Hall

Keyword(s):

Physiological Responses ◽

Dry Weight ◽

Poor Quality ◽

Rosa Hybrida ◽

Growth Reduction ◽

Flower Number ◽

Excellent Performance ◽

Shoot Dry Weight ◽

Greenhouse Study ◽

Substrate Moisture

A greenhouse study was conducted to quantify the irrigation requirements of two rose (Rosa hybrida L.) cultivars, RADrazz and Belinda’s Dream, which are widely valued for their ease of maintenance in landscapes, grown at four constant volumetric substrate moisture contents (SMCs) of 10%, 20%, 30%, and 40%. In both cultivars, there were no differences in growth and physiological responses between 30% and 40% SMC. In ‘RADrazz’, shoot dry weight (DW) was reduced by 25% and 86%, root DW was reduced by 27% and 71%, and flower number was reduced by 27% and 86% at 20% and 10% SMC, respectively, compared with 30% SMC. Midday leaf water potential (ψ), photosynthesis (Pn), stomatal conductance (gS), and transpiration (E) were highest at 30% and 40% SMC and they were lowest at 10% SMC. In ‘Belinda’s Dream’, shoot DW was reduced by 30% and 87%, root DW was reduced by 35% and 81%, and flower number was reduced by 42% and 75% at 20% and 10% SMC, respectively, compared with 30% SMC. Midday ψ was least negative at 40% SMC, whereas it was most negative at 10% SMC. There were no significant differences in midday ψ between 20% and 30% SMC. Pn, gS, and E were highest at 30% and 40% SMC and lowest at 10% SMC. In summary, plants at 30% and 40% SMC maintained the highest shoot and root DW, flower number, midday ψ, Pn, gS, and E. Water applied at 30% and 20% SMC was reduced by 31% and 70% compared with 40% SMC with excellent performance at 30% SMC and acceptable growth and quality at 20% SMC. The 10% SMC led to significant growth reduction, poor quality, and 25% mortality.

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EFFECT OF MINERAL DEFICIENCY ON MORPHOLOGICAL AND PHYSIOLOGICAL PARAMETERS AND ON SHOOT AND ROOT MINERAL PARTITIONING IN THREE SUNFLOWER VARIETIES / EFECTO DE LA FALTA DE ELEMENTOS MINERALAS SOBRE LOS PARAMENTROS MORFOLOGICOS Y FISIOLOGICOS Y REPARTICION DE ELEMENTOS MINERALES DE LA PARTE SOBRE EL SUELO Y DE LA RAIZ EN TRES VARIEDADES / INFLUENCE DE LA CARENCE D’ÉLÉMENTS MINÉRAUX SUR LES PARAMÈTRES MORPHOLOGIQUES ET PHYSIOLOGIQUES ET SUR LA DISTRIBUTION DES ÉLÉMENTS MINÉRAUX ENTRE LA PARTIE AÉRIENNE ET LA RACINE POUR TROIS SORTES DE TOURNESOL

Helia ◽

10.1515/helia.2001.24.35.135 ◽

2001 ◽

Vol 24 (35) ◽

pp. 135-148

Author(s):

Mohammed El Midaoui ◽

Ahmed Talouizte ◽

Benbella Mohamed ◽

Serieys Hervé ◽

Ait Houssa Abdelhadi ◽

...

Keyword(s):

Leaf Area ◽

Dry Matter ◽

Growth Parameters ◽

Dry Weight ◽

Mineral Deficiency ◽

P Deficiency ◽

Plant Parts ◽

Shoot Dry Weight ◽

K Deficiency ◽

Matter Effect

SUMMARYAn experiment has been carried out in order to study the behaviour under mineral deficiency of three sunflower genotypes, a population variety (Oro 9) and two hybrids (Mirasol and Albena). Sunflower seedlings were submitted to five treatments: N deficiency (N0), P deficiency (P0), K deficiency (K0), N and K deficiency (N0K0) and a control. Plants were harvested when they reached 3-4 true pairs of leaves. Growth parameters measured (height, total leaf area, root length, root and shoot dry mater) were all significantly reduced by mineral deficiency. Leaf area was most reduced by N0 (-61%) and P0 (-56%). Total dry matter was most affected by N0 (-63%) and by N0K0 (-66%). Genotype comparisons showed that Oro 9 had the highest shoot dry matter while Albena had the lowest root dry matter. Effect of mineral deficiency on content and partitioning of N, P, K, Ca and Na was significant and varied according to treatments and among plant parts. Shoot dry weight was significantly correlated with root N content (r2=0.81) and root K content (r2=-0.61) for N0 and K0.

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Applications of plant growth promoting bacteria and Trichoderma spp. for controlling Orobanche crenata in faba bean

Bulletin of the National Research Centre ◽

10.1186/s42269-019-0263-y ◽

2020 ◽

Vol 44 (1) ◽

Cited By ~ 1

Author(s):

Mahmoud Ahmed Touny El-Dabaa ◽

Hassan Abd-El-Khair

Keyword(s):

Plant Growth ◽

Faba Bean ◽

Growth Parameters ◽

Dry Weight ◽

Research Centre ◽

Plant Growth Promoting Bacteria ◽

Fresh Weight ◽

Orobanche Crenata ◽

Trichoderma Spp ◽

Shoot Dry Weight

Abstract Background Orobanche crenata is an obligate root parasite belonging to Orbanchaceae. Broomrape causes great damage to the faba bean. Several attempts were applied for controlling parasitic weeds. So, the aim of this work is to study the application of Trichoderma spp. as well as three rhizobacteria species in comparison to herbicidal effect of Glyphosate (Glialka 48% WSC) for controlling broomrape infesting faba bean (Vicia faba). Materials and methods Three pot experiments were carried out in the greenhouse of the National Research Centre, Dokki, Giza, Egypt during two successive winter seasons. Trichoderma inocula were adjusted to 3.6 × 108 propagules/ml and the bacterium inocula were adjusted at 107–109 colony-forming unit (CFU)/ml. All treatments were applied, before 1 week of sowing, at rate of 50 ml per pot in experiments I and II, while 100 ml per pot in experiment III. Results Trichoderma spp. (T. harzianum, T. viride and T. vierns) as well as three rhizobacteria species (Pseudomonas fluorescens, Bacillus subtilis and Bacillus pumilus) enhanced the growth parameters in faba bean plants, i.e. shoot length, shoot fresh weight, shoot dry weight and leaf number in the first experiment when applied without O. crenata infection. In the second experiment, all bio-control could protect plants against O. crenata infection, where it had better juvenile number reduction, than glyphosate after 2 months of application. Both B. subtilis and B. pumilus had the highest reduction to juvenile fresh weight, while their effect was equal to herbicide for juvenile dry weight, respectively. The bio-control agents had high effects until the 4th month, but it was less than that of the herbicide. In experiment III, the bio-control agents could highly reduce the juvenile parameters after 2 months, as well as juvenile fresh weight and juvenile dry weight after 4 months, than the herbicide, respectively. The bio-control agents were effective until 6 months, but less than the herbicide effect. All bio-control treatments highly increased the plant growth parameters, than the herbicide. Conclusion The application of Trichoderma spp. as well as rhizobacteria species could play an important role in controlling broomrape in faba bean as a natural bioherbicide.

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Foliar applications of bio-fabricated selenium nanoparticles to improve the growth of wheat plants under drought stress

Green Processing and Synthesis ◽

10.1515/gps-2020-0067 ◽

2020 ◽

Vol 9 (1) ◽

pp. 706-714

Author(s):

Muhammad Ikram ◽

Naveed Iqbal Raja ◽

Bilal Javed ◽

Zia-ur-Rehman Mashwani ◽

Mubashir Hussain ◽

...

Keyword(s):

Drought Stress ◽

Field Capacity ◽

Dry Weight ◽

Positive Control ◽

Morphological Characterization ◽

Leaf Length ◽

Selenium Nanoparticles ◽

Fresh Weight ◽

Wheat Varieties ◽

Shoot Dry Weight

AbstractThe present study was aimed to biosynthesize selenium nanoparticles (SeNPs) and assess their foliar applications to improve the growth of wheat plants under controlled irrigation and drought stress. Bud aqueous extract of Allium sativum L. was used as a reducing and stabilizing agent of SeNPs followed by their optical and morphological characterization by using ultraviolet-visible spectroscopy, scanning electron microscopy, Fourier-transform infrared, and energy dispersive X-ray analysis. Various concentrations of SeNPs (10, 20, 30, and 40 mg/L) were applied exogenously to drought-tolerant (V1) and drought-susceptible (V2) wheat varieties at the trifoliate stage. Under the positive control conditions, plants were irrigated with 450 mL of water/pot (100% field capacity); and under water-deficit environment, plants were irrigated with 160 mL of water/pot (35% field capacity). Remarkable increase in plant height, shoot length, shoot fresh weight, shoot dry weight, root length, root fresh weight, root dry weight, leaf area, leaf number, and leaf length has been observed when 30 mg/L concentration of SeNPs was used. However, the plant morphological parameters decreased gradually at higher concentrations (40 mg/L) in both selected wheat varieties. Therefore, 30 mg/L concentration of SeNPs was found most preferable to enhance the growth of selected wheat varieties under normal and water-deficient conditions.

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Evaluation of a Substrate-applied Humectant to Mitigate Drought Stress in Young, Container-grown Plants

Journal of Environmental Horticulture ◽

10.24266/0738-2898-33.3.137 ◽

2015 ◽

Vol 33 (3) ◽

pp. 137-141

Author(s):

Bruce R. Roberts ◽

Chris Wolverton ◽

Samantha West

Keyword(s):

Drought Stress ◽

Root Growth ◽

Shoot Growth ◽

Dry Weight ◽

Root:Shoot Ratio ◽

Xylem Water Potential ◽

Bedding Plants ◽

Shoot Dry Weight ◽

Soilless Substrate ◽

Absorbing Roots

The efficacy of treating soilless substrate with a commercial humectant was tested as a means of suppressing drought stress in 4-week-old container-grown Zinnia elegans Jacq. ‘Thumbelina’. The humectant was applied as a substrate amendment at concentrations of 0.0, 0.8, 1.6 and 3.2% by volume prior to withholding irrigation. An untreated, well-watered control was also included. The substrate of treated plants was allowed to dry until the foliage wilted, at which time the plants were harvested and the following measurements taken: number of days to wilt (DTW), xylem water potential (ψx), shoot growth (shoot dry weight, leaf area) and root growth (length, diameter, surface area, volume, dry weight). For drought-stressed plants grown in humectant-treated substrate at concentrations of 1.6 and 3.2%, DTW increased 25 and 33%, respectively. A linear decrease in ψx was observed as the concentration of humectant increased from 0.0 to 3.2%. Linear trends were also noted for both volumetric moisture content (positive) and evapotranspiration (negative) as the concentration of humectant increased. For non-irrigated, untreated plants, stress inhibited shoot growth more than root growth, resulting in a lower root:shoot ratio. For non-irrigated, humectant-treated plants, the length of fine, water-absorbing roots increased linearly as humectant concentration increased from 0.0 to 3.2%. Using humectant-amended substrates may be a management option for mitigating the symptoms of drought stress during the production of container-grown bedding plants such as Z. elegans.

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Confirmation of Glyphosate-Resistant Horseweed (Conyza canadensis) in Montana Cereal Production and Response to POST Herbicides

Weed Technology ◽

10.1017/wet.2017.49 ◽

2017 ◽

Vol 31 (6) ◽

pp. 799-810 ◽

Cited By ~ 5

Author(s):

Vipan Kumar ◽

Prashant Jha ◽

Amit J. Jhala

Keyword(s):

Great Plains ◽

Dose Response ◽

Best Management Practices ◽

Management Practices ◽

Dry Weight ◽

Shoot Dry Weight ◽

Greenhouse Study ◽

Whole Plant ◽

Cereal Production ◽

Sites Of Action

In recent years, horseweed has become an increasing problem in Montana. To confirm and characterize the level of glyphosate resistance, seeds were collected from putative glyphosate-resistant (GR) horseweed (GR-MT) plants in a wheat–fallow field in McCone County, MT. Known GR (GR-NE) and glyphosate-susceptible (GS-NE) horseweed accessions from Lincoln, NE, were included for comparison in dose–response and shikimate accumulation studies. Whole-plant glyphosate dose–response experiments conducted at the early- (5- to 8-cm diameter) and late- (12- to 15-cm diameter) rosette stages of horseweed indicated that GR-MT accessions had a 2.5- to 4.0-fold level of resistance to glyphosate relative to the GS-NE accession, on the basis of shoot dry weight (GR50values). The level of resistance was 3.1- to 7.9-fold on the basis of visually assessed injury estimates (I50values). At the whole-plant level, about 2.1- to 4.5-fold higher shikimate accumulation was observed in the GS-NE accession compared with the GR-MT and GR-NE accessions over a 10-d period after glyphosate was applied at 1,260 g ae ha−1. In a separate greenhouse study, all three horseweed accessions were also screened with alternate POST herbicides registered for use in wheat–fallow rotations. The majority of the tested herbicides provided ≥90% injury at the field-use rates for all three horseweed accessions 3 wk after treatment. This is the first published report on the occurrence of GR horseweed in Montana cereal production. Increased awareness and adoption of best management practices, including the use of diversified (based on multiple sites of action) herbicide programs highlighted in this study, would aid in mitigating the further spread of GR horseweed in the cereal production fields of the U.S. Great Plains.

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Growth response of pigeon pea (Cajanus cajan L. Millsp) on saline and alfisol soils

E3S Web of Conferences ◽

10.1051/e3sconf/202130601010 ◽

2021 ◽

Vol 306 ◽

pp. 01010

Author(s):

M. Soedarjo

Keyword(s):

Growth Retardation ◽

Saline Soil ◽

Growth Parameters ◽

Research Work ◽

Dry Weight ◽

Pigeon Pea ◽

Saline Soils ◽

Growth Responses ◽

High Concentration ◽

Shoot Dry Weight

As an archipelago country, Indonesia is surrounded by abundant saline soils which could be potential for growing food crops. The research work was conducted to study the growth responses of some pigeon pea genotypes on saline soils. The genotypes of Pigeon pea (LG Kidul, Mega, 90024, 91043 and 94028), as treatment, were grown on Alfisol soil (non-saline) and on saline soil. The experiment was carried out using completely randomized design and replicated three times. All data observed were analyzed by employing standard deviation from 3 replicates. The results of present research work revealed a significant growth retardation of pigeon pea when grown on saline soil. All growth parameters, plant height, plant diameter, root dry weight, and shoot dry weight were significantly lower on saline soil than on Alfisol soil. High concentration of Na+ was observed in roots, shoots and leaves of pigeon pea indicating growth retardation and toxicity symptoms of pigeon pea on saline soil was due to Na+.

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ASSESSING THE NITROGEN FIXATION ABILITIES OF NEWLY DEVELOPED PHASEOLUS VULGARIS LINES

HortScience ◽

10.21273/hortsci.27.6.662e ◽

1992 ◽

Vol 27 (6) ◽

pp. 662e-662

Author(s):

Dyremple B. Marsh ◽

Wayne McLaughlin ◽

James S. Beaver

Keyword(s):

Phaseolus Vulgaris ◽

Dry Weight ◽

Tropical Regions ◽

Breeding Lines ◽

Shoot Dry Weight ◽

Greenhouse Study ◽

Kidney Beans ◽

Randomized Design ◽

Red Kidney Bean ◽

Completely Randomized Design

Methods to improve the grain yield of red kidney bean without the addition of commercially fixed nitrogen will have significant benefits to farmers in Jamaica and other tropical regions. Red kidney beans provide a major portion of the dietary protein for most families in these regions. Our experimental objective was to evaluate the nitrogen fixing capabilities of several breeding lines of Phaseolus vulgaris when inoculated with Rhizobium strains isolated from Jamaican soils. Surface sterilized seeds of 11 Phaseolus lines were inoculated with inoculum prepared from 5 day old Rhizobium YEM mixture. Rhizobium used were T2 and B17 from Jamaica and UMR 1889. The greenhouse study was arranged as a completely randomized design. Bean lines 9056-101, 9056-98B, 8954-5 and 8954-4 showed improved nodulation and N2 fixation when inoculated with UMR 1899. The combination of breeding line 8954-5 and Rhizobium strain B17 produced the highest nodule number and shoot dry weight of 193 and 0.72 g, respectively. The Rhizobium strain B17showed some ability to compete successfully for nodule sites against known effective strains.

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Response of Selected Garden Roses to Drought Stress

HortScience ◽

10.21273/hortsci.47.8.1050 ◽

2012 ◽

Vol 47 (8) ◽

pp. 1050-1055 ◽

Cited By ~ 8

Author(s):

Xiaoya Cai ◽

Terri Starman ◽

Genhua Niu ◽

Charles Hall ◽

Leonardo Lombardini

Keyword(s):

Drought Stress ◽

Root Growth ◽

Field Capacity ◽

Leaf Water ◽

The Other ◽

Flower Number ◽

Drought Treatment ◽

Greenhouse Study ◽

Drought Tolerant ◽

Substrate Moisture

A greenhouse study was conducted to evaluate the response of four garden roses (Rosa ×hybrid L.), ‘RADrazz’, ‘Belinda’s Dream’, ‘Old Blush’, and ‘Marie Pavie’, to drought stress. Plants grown in containers were subjected to two watering treatments, well-irrigated [water as needed: ≈35% substrate moisture content (SMC) at re-watering] and cyclic drought stress (withholding irrigation until plants exhibit incipient wilting: ≈10% SMC, then re-watering to field capacity for subsequent dry down). Shoot growth and flower number were reduced in the drought treatment compared with the well-irrigated plants in all cultivars with least reduction in ‘RADrazz’. Drought stress reduced root growth in ‘Belinda’s Dream’ and ‘Marie Pavie’, whereas there was no difference in root growth in ‘RADrazz’ and ‘Old Blush’. Decreased SMC induced reduction in net photosynthetic rate (Pn), stomatal conductance (gS), transpiration rate (E), and midday leaf water potential (ψ). Leaf water use efficiency (WUE) increased as SMC decreased in all cultivars. However, the relationship between these physiological parameters and SMC differed among the cultivars. At SMC between 10% and 20%, ‘RADrazz’ had higher Pn, gS, E, and WUE compared with the other three cultivars. Therefore, ‘RADrazz’ was the most drought-tolerant during container production among the cultivars investigated. With lower gas exchange rates and greater reduction in flower number at low SMC, ‘Marie Pavie’ was less drought-tolerant compared with the other three cultivars.

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