scholarly journals Pepper Seedling Growth Response to Drought Stress and Exogenous Abscisic Acid

1992 ◽  
Vol 117 (3) ◽  
pp. 389-393 ◽  
Author(s):  
Daniel I. Leskovar ◽  
Daniel J. Cantliffe

ABA and drought stress were evaluated on growth morphology and dry weight of pepper (Capsicum annuum L.) seedlings subjected to continuous watering (CV) or alternate watering (AW) subflotation irrigation. When ABA (10-4m) was sprayed on to leaves 28, 32, or 37 days after seeding (DAS), leaf growth was limited relative to the controls. Root dry weight, basal root count, and diameter decreased in AW compared with CW-treated seedlings. ABA did not influence root growth of the transplants or subsequent total fruit yield. When ABA was applied to leaves at 20,23, or 29 DAS, there was a transient inhibition of leaf weight increase, but root growth was unaffected. Exogenous ABA may have a practical application as a substitute for drought stress to control transplant growth in the nursery. Chemical name used: abscisic acid (ABA).

2015 ◽  
Vol 33 (3) ◽  
pp. 137-141
Author(s):  
Bruce R. Roberts ◽  
Chris Wolverton ◽  
Samantha West

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.


1992 ◽  
Vol 22 (5) ◽  
pp. 740-749 ◽  
Author(s):  
R. van den Driessche

Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco), lodgepole pine (Pinuscontorta Dougl.), and white spruce (Piceaglauca (Moench) Voss) seedlings, each represented by two seed lots, were grown in Styroblock containers in a greenhouse and plastic shelter house from February 1989 to January 1990. The seedlings were exposed to two nitrogen (N) treatments and three potassium (K) treatments arranged factorially within three drought treatments. After winter storage, seedlings from a complete set of treatments were planted into hygric, mesic, and xeric sand beds during 12–14 March. Increasing nursery drought stress increased survival of Douglas-fir and lodgepole pine after planting, and high N treatment level increased survival of lodgepole pine and white spruce. Under xeric conditions, combined nursery drought and high N treatments increased survival of lodgepole pine by 33%, indicating the importance of nursery cultural regime for stock quality. Increase in nursery drought decreased seedling size relatively little, but increase in N increased seedling size one season after planting. A positive relationship between shoot/root ratio and survival in lodgepole pine and white spruce indicated that increase in N increased both shoot growth and drought resistance over the N range investigated. Only Douglas-fir showed an interaction between drought and N treatment and a small response in both survival and dry weight to K. Root growth capacity, measured at the time of planting, showed an approximate doubling in all species due to high N treatment, and was also increased in white spruce by drought stress. Survival and root growth capacity were poorly correlated, but dry-weight growth in sand beds was well correlated with root growth capacity. Shoot dry weight and percent N in shoots measured after nursery growth were correlated with root growth capacity. Manipulation of root growth capacity by changing nursery treatment was apparently possible without altering resistance to drought stress after planting.


2003 ◽  
Vol 128 (1) ◽  
pp. 36-41 ◽  
Author(s):  
Zhaolong Wang ◽  
Bingru Huang ◽  
Qingzhang Xu

Abscisic acid (ABA) is an important hormone regulating plant response to drought stress. The objective of this study was to investigate effects of exogenous ABA application on turf performance and physiological activities of kentucky bluegrass (Poa pratensis L.) in response to drought stress. Plants of two kentucky bluegrass cultivars, `Brilliant' (drought susceptible) and `Midnight' (drought tolerant), were treated with ABA (100 μm) or water by foliar application and then grown under drought stress (no irrigation) or well-watered (irrigation on alternate days) conditions in a growth chamber. The two cultivars responded similarly to ABA application under both watering regimes. Foliar application of ABA had no effects on turf quality or physiological parameters under well-watered conditions. ABA application, however, helped maintain higher turf quality and delayed the quality decline during drought stress, compared to the untreated control. ABA-treated plants exposed to drought stress had higher cell membrane stability, as indicated by less electrolyte leakage of leaves, and higher photochemical efficiency, expressed as Fv/Fm, compared to untreated plants. Leaf water potential was not significantly affected, whereas leaf turgor pressure increased with ABA application after 9 and 12 d of drought. Osmotic adjustment increased with ABA application, and was sustained for a longer period of drought in `Midnight' than in `Brilliant'. The results suggested that exogenous ABA application improved turf performance during drought in both drought-sensitive and tolerant cultivars of kentucky bluegrass. This positive effect of ABA could be related to increased osmotic adjustment, cell turgor maintenance, and reduced damage to cell membranes and the photosynthetic system.


1999 ◽  
Vol 50 (2) ◽  
pp. 223 ◽  
Author(s):  
J. K. Olsen ◽  
J. T. Schaefer ◽  
D. G. Edwards ◽  
M. N. Hunter ◽  
V. J. Galea ◽  
...  

The growth response of 2 vegetable crops to 5 rates of applied phosphorus (P)in the presence or absence of an existing network of extraradical mycorrhizalmycelium was determined in 2 greenhouse pot experiments (Expt 1, autumnwinter; Expt 2, summer autumn) using a low-P growth medium (6 or 5 mgNaHCO3-extractable P/kg for Expt 1 or 2,respectively). In both experiments, capsicum(Capsicum annuum L.) and tomato(Lycopersicon esculentum Mill.) plants were grown at 0(P1 ), 9.2 (P2), 27.5(P3 ), 82.5 (P4 ), or 248(P5) mg P/kg oven-dry soil (spot-placed at sowing)within a nylon mesh (pore size 44 µm). The mesh excluded roots from theoriginal sunflower (Helianthus annuus L.) host plants,to which either live (VAM+) or killed (VAM–) mycorrhizal[Glomus etunicatum Becker & Gerdemann andGlomus mosseae (Nicol. & Gerd.) Gerdemann & Trappe] inoculum was added at sowing. The mesh did allow fungal hyphae togrow into the growth medium contained by the mesh.Whereas VAM+ plants generally had higher P concentrations in indextissues than VAM– plants at low P rates, a concomitant increase in drymatter yield was restricted to the P1 rate. AtP1 in Expt 2, the increase in the dry weight of wholeplants as a result of VAM colonisation was as large as 91.7-fold and 17.9-foldfor capsicum and tomato, respectively. Root starch analysis indicated that thelower dry matter yields of VAM+ plants than of VAM– plants at≥P2 could be attributed to insufficient photosynthateproduction by VAM+ plants to meet the carbon (C) demand of both host andendophytes within the relatively low-light environment of the greenhouse(average daily solar irradiance of 8.4 MJ/m2 forExpt 1 and 13.4 MJ/m2 for Expt 2).The growth response of vegetable crops grown within the greenhouse fromcolonisation by an established mycorrhizal mycelium appears to depend on acritical balance of P and C supply; i.e. at P1, P wasmore limiting than C, and the increased uptake of P as a result ofcolonisation of plant roots by VAM resulted in a growth response. At higher Prates, C was more limiting than P due to low light in the greenhouse, and theadditional demand for photosynthate imposed by the endophytes on the hostresulted in a growth depression relative to non-mycorrhizal plants.


2019 ◽  
Vol 46 (2) ◽  
pp. 165 ◽  
Author(s):  
Xiaonan Ma ◽  
Xiaoran Zhang ◽  
Ling Yang ◽  
Mengmeng Tang ◽  
Kai Wang ◽  
...  

Abscisic acid (ABA) is a crucial factor that affects primary root tip growth in plants. Previous research suggests that reactive oxygen species (ROS), especially hydrogen peroxide, are important regulators of ABA signalling in root growth of Arabidopsis. PROLINE-RICH EXTENSIN-LIKE RECEPTOR KINASE 4 (PERK4) plays an important role in ABA responses. Arabidopsis perk4 mutants display attenuated sensitivity to ABA, especially in primary root growth. To gain insights into the mechanism(s) of PERK4-associated ABA inhibition of root growth, in this study we investigated the involvement of ROS in this process. Normal ROS accumulation in the primary root in response to exogenous ABA treatment was not observed in perk4 mutants. PERK4 deficiency prohibits ABA-induced expression of RESPIRATORY BURST OXIDASE HOMOLOGUE (RBOH) genes, therefore the perk4-1 mutant showed decreased production of ROS in the root. The perk4-1/rbohc double mutant displayed the same phenotype as the perk4 and rbohc single mutants in response to exogenous ABA treatment. The results suggest that PERK4-stimulated ROS accumulation during ABA-regulated primary root growth may be mediated by RBOHC.


2000 ◽  
Vol 80 (4) ◽  
pp. 875-877 ◽  
Author(s):  
A. Liptay ◽  
P. Sikkema

Control of tomato (Lycopersicon esculentum Mill.) seedling growth and height during production in the greenhouse is critical for efficient subsequent transplanting and acceptable field performance. Height can be reduced by P fertilisation. Eliminating P from nutrient solutions severely restricted growth. When fed a 10 mg P L−1 in the nutrient solution, seedlings were 11 cm tall after 49 d of growth, but only 3 cm tall without P. Intermediate P reduced height within this range. Transplanting was simulated after 49 d of seedling production by transferring the transplants to a temperature-controlled root chamber in larger volume cells plus fertilisation with a complete nutrient solution. Transplant growth with a complete nutrient solution caused differential growth according to the prior P feeding regime. New root growth in the various treatments was dependent on root growth during the transplant stage. However, shoot growth differed greatly among the P levels. Seedlings grown without any P during transplant production grew very slowly with only a 25% increase in leaf growth after 9 d. With the 2 mg L−1 feeding during transplant production of leaf dry weight increased over 200% during the 9-d period. In conclusion, seedling growth restriction can be achieved by P deprivation; the amount of P deprivation, however, affects subsequent seedling growth. Key words: Phosphorus, nutrients, tomato, transplant.


2019 ◽  
Author(s):  
Zhongshuai Gai ◽  
Yu Wang ◽  
Yiqian Ding ◽  
Wenjun Qian ◽  
Hui Xie ◽  
...  

Abstract Background: Abscisic acid (ABA) is an important phytohormone responsible for activating drought resistance, but the regulation mechanism of exogenous ABA on tea plants under drought stress was rarely reported. Results: The results showed that the exogenous ABA significantly induced the metabolic pathways of tea leaves under drought stress, including the chlorophyll synthesis, photosynthesis, sucrose and starch metabolism, TCA cycle, glycolysis, lipid metabolism and flavonoids biosynthesis. In which, the exogenous ABA could up-regulated the genes related to lipid metabolism and flavonoid biosynthesis, including LPCAT , ALDH, FLS, CHI, DFR, and down-regulated the genes related to lipid metabolism and flavonoid biosynthesis, including FATB, EKI, DGK , PAL, 4CL . The exogenous ABA could also increase the contents of flavone, anthocyanins, flavonol, isoflavone of tea leaves under drought stress, including delphinidin 3-O-glucosidewere, cyanidin 3-O-rutinoside, kaempferitrin, sakuranetin, prunetin, kaempferol, and decrease the contents of glycerophospholipids, glycerolipids and fatty acids of tea leaves under drought stress, including LysoPE 14:0, LysoPE 16:0, LysoPE 18:0, LysoPE 18:1, LysoPC 15:1 and LysoPC 16:0. And there were strong correlations between the genes and metabolites. Conclusions: The results suggested that the exogenous ABA could alleviate the damages of tea leaves under drought stress through inducing the expressions of the genes and altering the contents of metabolites in response to drought stress. The data also provide a good foundation for further research on the roles of the genes and metabolites in response to ABA.


2006 ◽  
Vol 20 (2) ◽  
pp. 389-393 ◽  
Author(s):  
Ronald J. Levy ◽  
Jason A. Bond ◽  
Eric P. Webster ◽  
James L. Griffin ◽  
Wei P. Zhang ◽  
...  

Greenhouse research was conducted to evaluate shoot and root growth response of imidazolinone-tolerant (IT) rice cultivars to imazethapyr applied postemergence at various rates and application timings. Imazethapyr was applied at 70, 140, and 280 g ai/ha to IT cultivars ‘CL 121’ and ‘CL 161’ in the one- to two-leaf and three- to four-leaf growth stages. Imazethapyr applied to one- to two-leaf or three- to four-leaf rice at 70, 140, and 280 g/ha was more injurious to CL 121 than to CL 161. At 3 wk after treatment (WAT), CL 121 was injured 23 to 38% regardless of application timing. In contrast, CL 161 was injured no more than 11% at 3 WAT. Shoot:root ratio for CL 161 was not affected by imazethapyr application. For CL 121, shoot:root ratio was lower following imazethapyr at 280 g/ha than at 70 or 140 g/ha. Based on shoot fresh weight following imazethapyr at 70 g/ha, CL 161 was 1.8 times more tolerant than CL 121 at 2 WAT and 1.3 times more tolerant at 3 WAT. The IT rice cultivar CL 161 is inherently more tolerant to imazethapyr than is CL 121 based on visual injury and shoot and root growth.


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