scholarly journals Effects of 6-Benzyladenine, γ-Aminobutyric Acid, and Nitric Oxide on Plant Growth, Photochemical Efficiency, and Ion Accumulation of Perennial Ryegrass Cultivars to Salinity Stress

HortScience ◽  
2019 ◽  
Vol 54 (8) ◽  
pp. 1418-1422 ◽  
Author(s):  
Zhongjie Ji ◽  
James J. Camberato ◽  
Cankui Zhang ◽  
Yiwei Jiang

Plant growth regulators (PGRs) can mediate plant response to salinity stress. Perennial ryegrass (Lolium perenne) cultivars of BrightStar SLT, Catalina, Inspire, and SR4660ST were exposed to 0, 100, or 200 mm NaCl for 14 d. 6-benzyladenine (6-BA, 10 µm), γ-aminobutyric acid (GABA, 500 µm), nitric oxide (NO, 200 µm), and H2O were applied to the foliage every day for 3 days before stress and then every 2 days during salinity stress. Averaged across the four cultivars, a foliar spray of NO increased leaf fresh weight (FW) and dry weight (DW) at 0 mm NaCl, whereas application of 6-BA increased DW and GABA reduced Na+ concentration at 100 mm NaCl, compared with H2O application. Plants treated with 6-BA, GABA, and NO had less chlorotic and necrotic leaf tissue than plants treated with H2O at 200 mm NaCl. Spray of 6-BA and NO increased FW and DW, but application of all three PGRs maintained higher leaf photochemical efficiency and lower leaf Na+ concentration compared with H2O treatment at 200 mm NaCl. Across salinity and PGR treatments, ‘Catalina’ exhibited higher plant height than the ‘Inspire’ and SR4660ST, and SR4660ST had relatively higher Na+ concentration than ‘Catalina’ but not ‘BrightStar SLT’ and ‘Inspire’. The results demonstrate that 6-BA, GABA, and NO ameliorated salinity tolerance of perennial ryegrass by improving growth and photochemical efficiency or reducing Na+ accumulation.

2018 ◽  
Vol 8 ◽  
pp. 1415-1423 ◽  
Author(s):  
Afnan Freije

The effect of foliar ALA application on the internal ALA concentration in tomato plants grown in soil containing high levels of NaCl  was investigated. Six week old plants were treated with 100, 50, and 25 mmol/L NaCl on a weekly basis and they were simultaneously treated with 5-ALA at a concentration of 5%  by foliar spray. The effect of foliar ALA application on plant growth, chlorophyll contents and internal ALA concentration was studied. The internal ALA shoot concentrations ranged between 27.50±2.12 and 34.35±1.48 µg g-1 dry weight with no significant difference (p<0.05) recorded between plants treated with NaCl alone and those treated with both NaCl and ALA. The concentrations of chlorophyll a and b were elevated only in tomato plants treated with NaCl and ALA, whereas their levels decreased in plants treated with NaCl only. An adverse significant effect (p<0.05) of salinity stress was recorded on plants length, number of leaves, shoot and root fresh and dry weight. However, no significant difference  (p<0.05) was observed in plants treated with  NaCl alone with those treated with  NaCl plus ALA in comparison to the control. The results of the present study suggested that foliar ALA treatment had no effect on the Na and Cl uptake, the internal ALA concentration, and had no role in adverting the effects of salinity on plant growth. The present study has proven that foliar ALA is directly used by the plant for the synthesis of chlorophyll in order to increase the photosynthetic rate and thus to help tomato plants to survive the salinity stress.


2016 ◽  
Vol 141 (3) ◽  
pp. 233-241 ◽  
Author(s):  
Liang Cheng ◽  
Ning Zhang ◽  
Bingru Huang

The accumulation of 1-aminocyclopropane-1-carboxylate (ACC), which is a precursor for ethylene production, in plant roots exposed to salinity stress can be detrimental to plant growth. The objectives of this study were to determine whether inoculating roots with bacteria containing deaminase enzymes that break down ACC (ACC-deaminase) could improve plant tolerance to salinity in perennial ryegrass (Lolium perenne) and to examine growth and physiological factors, as well as nutrition status of plants affected by the ACC-deaminase bacteria inoculation under salinity stress. Plants of perennial ryegrass (cv. Pangea) were inoculated with either Burkholderia phytofirmans PsJN or Burkholderia gladioli RU1 and irrigated with either fresh water (control) or a 250 mm NaCl solution to induce salinity stress. The bacterium-inoculated plants had less ACC content in shoots and roots under both nonstressed and salinity conditions. Salinity stress inhibited root and shoot growth, but the bacterium-inoculated plants exhibited higher visual turf quality (TQ), tiller number, root biomass, shoot biomass, leaf water content, and photochemical efficiency, as well as lower cellular electrolyte leakage (EL) under salinity stress. Plants inoculated with bacteria had lower sodium content and higher potassium to sodium ratios in shoots under salinity stress. Shoot and root nitrogen content and shoot potassium content increased, whereas shoot and root calcium, magnesium, iron, and aluminum content all decreased due to bacterial inoculation under salinity treatment. ACC-deaminase bacteria inoculation of roots was effective in improving salinity tolerance of perennial ryegrass and could be incorporated into turfgrass maintenance programs in salt-affected soils.


Author(s):  
Qiannan Hu ◽  
Fei Ding ◽  
Mingna Li ◽  
Xiaxiang Zhang ◽  
Shuoxin Zhang ◽  
...  

Accelerated or premature leaf senescence induced by dark conditions could be associated with chlorophyll degradation and regulated by hormones. To study the effects of strigolactone (SL) on dark-induced leaf senescence and to examine the interaction effects of SL and ethylene on regulating dark-induced leaf senescence, plants of perennial ryegrass (Lolium perenne) exposed to darkness for 8 days were treated with a synthetic SL analogue (GR24), aminoethoxyvinyl glycine [AVG (an ethylene biosynthesis inhibitor)], or SL and AVG by foliar spray. Chlorophyll content, photochemical efficiency, electrolyte leakage, and ethylene production were measured. Expressions of genes associated with leaf senescence, SL biosynthesis and signaling, ethylene biosynthesis and signaling, and chlorophyll biosynthesis and degradation were determined. Foliar application of GR24 promoted leaf senescence in perennial ryegrass grown in darkness, and the intensity of action increased with the GR24 concentration. SL-accelerated leaf senescence was associated with the downregulation of four chlorophyll biosynthesis-associated genes and upregulation of four chlorophyll degradation-associated genes. AVG had functions counteractive to SL, suppressing dark-induced leaf senescence by downregulating chlorophyll degradation genes and SL synthesis genes. Our results suggested that SL and ethylene interactively regulated leaf senescence, mainly by controlling chlorophyll degradation induced by darkness in perennial ryegrass.


2017 ◽  
Vol 142 (6) ◽  
pp. 476-483 ◽  
Author(s):  
Xin Song ◽  
Suo-min Wang ◽  
Yiwei Jiang

Perennial ryegrass (Lolium perenne) is a popular cool-season and forage grass around the world. Salinity stress may cause nutrient disorders that influence the growth and physiology of perennial ryegrass. The objective of this study was to identify the genotypic variations in growth traits and nutrient elements in relation to salinity tolerance in perennial ryegrass. Eight accessions of perennial ryegrass [PI265351 (Chile), PI418707 (Romania), PI303012 (UK), PI303033 (The Netherlands), PI545593 (Turkey), PI577264 (UK), PI610927 (Tunisia), and PI632590 (Morocco)] were subjected to 0 (control, no salinity) and 300 mm NaCl for 10 d in a greenhouse. Across accessions, salinity stress decreased plant height (HT), leaf fresh weight (LFW), leaf dry weight (LDW), leaf water concentration (LWC), and concentration of N, C, Ca2+, Cu2+, K+, Mg2+, and K+/Na+ ratio and increased Na+ concentration. Negative correlations were found between C and Na+, whereas positive correlations of K+/Na+ with C and N were found under salinity treatment. The principal component analysis (PCA) showed that the first, second, and third principal components explained 40.2%, 24.9%, and 13.4% variations of all traits, respectively. Based on loading values from PCA analysis, LWC, Na+ concentration, and K+/Na+ ratio were chosen to evaluate salinity tolerance of accessions, and eight accessions were divided into the tolerant, moderate, and sensitive groups. The tolerant group had relatively higher LWC and K+/Na+ ratio and concentrations of C, P, and Fe2+ and lower Na+ concentrations than the other two groups, especially the sensitive groups. The result suggested that lower Na+ accumulation and higher K+/Na+ ratio and LWC were crucial strategies for achieving salinity tolerance of perennial ryegrass.


2017 ◽  
Vol 142 (2) ◽  
pp. 110-118 ◽  
Author(s):  
Xiujie Yin ◽  
Chao Zhang ◽  
Xin Song ◽  
Yiwei Jiang

Waterlogging can occur in salt-affected turfgrass sites. The objective of this study was to characterize growth and carbohydrate, lipid peroxidation, and nutrient levels in the leaves and roots of two perennial ryegrass (Lolium perenne) cultivars (Catalina and Inspire) to short-term simultaneous waterlogging and salinity stress. Previous research showed that ‘Catalina’ was relatively more tolerant to salinity but less tolerant to submergence than ‘Inspire’. Both cultivars were subjected to 3 and 7 days of waterlogging (W), salinity [S (300 mm NaCl)], and a combination of the two stresses (WS). Across the two cultivars, W alone had little effect on the plants, while both S and WS alone significantly decreased plant height (HT), leaf fresh weight (LFW), leaf dry weight (LDW), root fresh weight (RFW), root dry weight (RDW), leaf nitrogen (LN) and carbon (LC), and leaf and root K+ (RK+), and increased leaf water-soluble carbohydrate (LWSC) and root water-soluble carbohydrate (RWSC), malondialdehyde (MDA), and Na+ content, compared with the control. A decline in chlorophyll content (Chl) was found only at 7 days of WS. Leaf phosphorus (LP) content either decreased or remained unchanged but root phosphorus content increased under S and WS. Reductions in LFW and LDW were found at 3 days of S and WS, whereas RFW and RDW were unaffected until 7 days of S or WS. Both cultivars responded similarly to W, S, and WS with a few exceptions on RDW, LWSC, leaf MDA (LMDA), and root MDA (RMDA). Although WS caused declines in Chl and resulted in higher leaf Na+ (LNa+) and root Na+ (RNa+) than S at 7 days of treatment, S and WS had similar effects on growth, carbohydrate, MDA, N, C, and phosphorus, and K+ content across the two cultivars. The results suggested that S alone largely accounted for the negative effects of WS on plant growth and physiology including alteration of carbohydrate and nutrient content as well as induction of lipid peroxidation.


Plants ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1687
Author(s):  
Pharada Rangseekaew ◽  
Adoración Barros-Rodríguez ◽  
Wasu Pathom-aree ◽  
Maximino Manzanera

Soil salinity is an enormous problem affecting global agricultural productivity. Deep-sea actinobacteria are interesting due to their salt tolerance mechanisms. In the present study, we aim to determine the ability of deep-sea Dermacoccus (D. barathri MT2.1T and D. profundi MT2.2T) to promote tomato seedlings under 150 mM NaCl compared with the terrestrial strain D. nishinomiyaensis DSM20448T. All strains exhibit in vitro plant growth-promoting traits of indole-3-acetic acid production, phosphate solubilization, and siderophore production. Tomato seedlings inoculated with D. barathri MT2.1T showed higher growth parameters (shoot and root length, dry weight, and chlorophyll content) than non-inoculated tomato and the terrestrial strain under 150 mM NaCl. In addition, hydrogen peroxide (H2O2) in leaves of tomatoes inoculated with deep-sea Dermacoccus was lower than the control seedlings. This observation suggested that deep-sea Dermacoccus mitigated salt stress by reducing oxidative stress caused by hydrogen peroxide. D. barathri MT2.1T showed no harmful effects on Caenorhabditis elegans, Daphnia magna, Eisenia foetida, and Escherichia coli MC4100 in biosafety tests. This evidence suggests that D. barathri MT2.1T would be safe for use in the environment. Our results highlight the potential of deep-sea Dermacoccus as a plant growth promoter for tomatoes under salinity stress.


2000 ◽  
Vol 18 (3) ◽  
pp. 132-136
Author(s):  
Mack Thetford ◽  
James B. Berry

Abstract The use of Primo (trinexapac-ethyl) was investigated as an alternative to pruning of container-grown woody ornamental species. A foliar spray of 469, 938, or 1407 ppm (0.5, 1.0 or 1.5 oz/gal) was applied to pruned plants. A nontreated control (water) and an industry control [Atrimmec (dikegulac-sodium)] were also included for comparison. Monthly mechanical pruning or no pruning treatments were imposed during the production period. Monthly pruning alone reduced the height of euonymus, forsythia, Chinese privet, waxleaf privet, and azalea. Efficacy of plant growth regulator treatments differed among the five species. Primo was not effective in suppressing the height or trimming dry weight of forsythia, Chinese privet, or waxleaf privet and provided only a transient suppression of euonymus and azalea.


2020 ◽  
Author(s):  
Lubna Lubna ◽  
Muhammad Aaqil Khan ◽  
Sajjad Asaf ◽  
Rehmatullah Jan ◽  
Muhammad Waqas ◽  
...  

Abstract Background Salinity stress is one of the most devastating environmental stress that inhibits plants growth and development. Many strategies including plant growth promoting fungi have been reported to mitigate salt stress. Results In this study, we adopted environmental friendly technique and screened different plant growth promoting fungi for different PGP traits and salinity stress. Among these isolate CSL1 were selected based on the basis of plant growth promoting characteristics producing IAA, GAs, organic acid and tolerance to NaCl stress. Furthermore, inoculation of fungal isolate CSL1 significantly increased shoot length (16%), root length (37%), shoot fresh and dry weight (19% and 25%), root fresh and dry weight (47 and 51%) and chlorophyll content (24%) under NaCl stress (200 mM). Endogenous ABA level (0.77 folds) were significantly decreased while SA contents (16%) were increase in CSL1 inoculated plants under NaCl stress. Similarly, higher level of antioxidants such as MDA (2 folds), SOA (29%), POD (8 folds) and PPO (3 folds) was observed in NaCl treated non-inoculated plants. ICP analysis showed an increase in Na+ (11 folds) and decrease in K+ content (15%). Furthermore, CSL-1 inoculation improved soybean adaptability against NaCl stress and a significant decrease in GmFDL19 expression (5 folds) GmNARK (4 folds) and GmSIN1 (3 folds) was observed. However, higher expression of GmAKT2 (15%) were observed in CSL-1 treated plants. Conclusion Fungal isolate CSL-1 have capability to mitigate salinity stress in soybean, increase plant growth and could be used as valuable ecofriendly microorganism resource, low cost based biotechnological approach for sustainable agriculture in salt affected areas.


1996 ◽  
Vol 6 (1) ◽  
pp. 19-20 ◽  
Author(s):  
John M. Ruter

Paclobutrazol was applied as a foliar spray, root-medium drench, and impregnated spike to `New Gold' lantana grown in 2.8-liter pots. Plants were treated 14 June 1993 at rates of 0, 0.5, and 1.0 mg a.i. paclobutrazol/pot and were harvested 27 July 1993 when control plants required further pruning. Impregnated spikes reduced plant size and flowering to a greater degree than spray applications. Drenches reduced root dry weight and biomass compared to spray applications. Plants treated with 0.5 and 1.0 mg a.i. paclobutrazol/pot were not different in regards to plant growth and flowering. Compared to nontreated controls, plants treated with paclobutrazol had a reduced growth index, decreased shoot and root dry weight, and fewer flowers with open florets. All plants in the study were marketable, even though growth control was considered excessive. Lower rates than used in this study should be considered for controlling growth. These results suggest that impregnated spike formulations of paclobutrazol may control plant growth in pine bark-based media.


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