Molybdenum deficiency in wheat results in lower dormancy levels via reduced ABA

1994 ◽  
Vol 4 (3) ◽  
pp. 329-333 ◽  
Author(s):  
A. T. Modi ◽  
A. L. P. Cairns

AbstractWheat which was grown in acid-washed sand and irrigated with a molybdenum-free nutrient solution was treated with various concentrations of molybdenum (Mo) as a foliar spray at the flag leaf stage. At maturity, dormancy levels and abscisic acid (ABA) content of the seed were determined. Seed dormancy and ABA content increased with increasing rates of Mo application. In a field experiment, wheat (cv. SST 66) was treated with 100 ppm Mo by foliar application at the flag leaf stage. Embryos were tested for sensitivity to exogenously applied ABA. Embryos from Mo-treated plants showed enhanced sensitivity to ABA-induced inhibition of germination. The Mo application also resulted in significantly higher levels of endogenous ABA and Mo in the seeds. It is postulated that Mo deficiency leads to a lack of dormancy in wheat via reduced synthesis of ABA.

2002 ◽  
Vol 12 (4) ◽  
pp. 239-252 ◽  
Author(s):  
Bernd Krock ◽  
Sybille Schmidt ◽  
Christian Hertweck ◽  
Ian T. Baldwin

AbstractThe native tobacco,Nicotiana attenuata, synchronizes its germination with the immediate post-fire environment with a combination of germination stimulants found in wood smoke and inhibitors from the unburned litter of the dominant vegetation. The inhibitors override the stimulants and prevent seeds from germinating maladaptively in unburned habitats adjacent to burns. To understand the physiological basis of this environmental control of germination, we tested several previously isolated signals, phytohormones and their respective biosynthesis inhibitors. The germination inhibitors methyl jasmonate (MeJA, a constituent of sagebrush litter), bornane-2,5-dione (BD, a constituent of juniper litter extract, JLE) and JLE did not alter abscisic acid (ABA) content of imbibed seeds. Treatment with the ABA biosynthesis inhibitor, fluridone, inhibited the dormancy-inducing effects of BD, JLE and MeJA, but surprisingly did not affect endogenous ABA levels in treated seeds. However, ABA leached from litter of the species, which dominate the plant community before fires, plays an important role in germination control. We conclude thatN. attenuataseeds, which can lie dormant in the soil for 150 years between fires, time their germination with the post-fire environment by responding to smoke, ABA and four terpenes (BD, 1,8-cineole, β-thujaplicin and camphor) leaching from the litter of the dominant vegetation.


2021 ◽  
Author(s):  
Marcilene Machado dos Santos Sarah ◽  
Renato de Mello Prado ◽  
Jonas Pereira de Souza Júnior ◽  
Gelza Carliane Marques Teixeira ◽  
João Carlos dos Santos Duarte ◽  
...  

Abstract Potassium (K) deficiency affects physiological performance and decreasing vegetative growth in common bean plants. However, silicon (Si) supplied via nutrient solution or foliar application may relieve nutritional stress. Thus, two experiments were carried out: initially, a test was performed to determine the best source and concentration of leaf-applied Si. Subsequently, the chosen Si source was applied via nutrient solution or via leaf to verify if it is efficient in alleviating the effects caused by K deficiency. To that end, a completely randomized 2 x 3 factorial design was used, with two levels of K: deficient (0.2 mmol L− 1 of K) and sufficient (6 mmol L− 1 of K); and Si: via nutrient solution (2 mmol L− 1 of Si) or foliar spray (5.4 mmol L− 1 of Si) and control (0 mmol L− 1 of Si). In the first experiment, foliar spraying with sodium silicate and stabilized potassium at a concentration of 5.4 mmol L− 1 was better in favoring the physiology of bean plants. In the second experiment, K deficiency without the addition of Si compromised the plant's growth. Si applied through nutrient solution or foliar spray relieved K deficiency stress, increasing chlorophylls and carotenoids content, photosynthetic activity, water use efficiency and vegetative growth.


2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Yosvanis Acanda ◽  
Óscar Martínez ◽  
María Jesús Prado ◽  
María Victoria González ◽  
Manuel Rey

Abstract Background Somatic embryogenesis in grapevines is a complex process that depends on many physiological and genetic factors. One of its main limitations is the process of precocious germination of the somatic embryos in differentiation medium. This process lowers plant conversion rates from the somatic embryos, and it is probably caused by a low endogenous abscisic acid (ABA) content. Results Precocious germination of the somatic embryos was successfully avoided by culturing grapevine cv. Mencía embryogenic aggregates over a semipermeable membrane extended on top of the differentiation medium. The weekly analysis of the endogenous ABA and ABA-glucosyl ester (ABA-GE) contents in the aggregates showed their rapid accumulation. The expression profiles of 9-cis-epoxycarotenoid dioxygenase (VvNCED1), 8′-hydroxylase (VvHyd2), UDP-glucosyltransferase (VvUGT) and β-glucosidase (VvBG2) genes in grapevine revealed that the occurrence of a first accumulation peak of endogenous ABA in the second week of culture over the semipermeable membrane was mainly dependent on the expression of the VvNCED1 gene. A second increase in the endogenous ABA content was observed in the fourth week of culture. At this point in the culture, our results suggest that of those genes involved in ABA accumulation, one (VvNCED1) was repressed, while another (VvBG2) was activated. Similarly, of those genes related to a reduction in ABA levels, one (VvUGT) was repressed while another (VvHyd2) was activated. The relative expression level of the VvNCED1 gene in embryogenic aggregates cultured under the same conditions and treated with exogenous ABA revealed the significant downregulation of this gene. Conclusions Our results demonstrated the involvement of ABA metabolism in the control of the maturation of grapevine somatic embryos cultured over a semipermeable membrane and two important control points for their endogenous ABA levels. Thus, subtle differences in the expression of the antagonistic genes that control ABA synthesis and degradation could be responsible for the final level of ABA during the maturation of grapevine somatic embryos in vitro. In addition, the treatment of somatic embryos with exogenous ABA suggested the feedback-based control of the expression of the VvNCED1 gene by ABA during the maturation of grapevine somatic embryos.


Author(s):  
Pavan Shinde ◽  
Ravi Hunje

The field experiment was carried out at WALMI Farm, University of Agricultural Sciences, Dharwad during 2015-16 and 2016-17 on organically maintained field to study the influence of soil application of organic manures and foliar spray of liquid biofertilizers on growth and seed yield of kabuli chickpea varieties. The experiment was laid in split plot design with three replications constituting two kabuli chickpea varieties and seven fertilizer treatments. The results revealed that, kabuli chickpea variety BG1105 (V1) recorded significantly higher values for seed yield and its yield attributes compared to MNK-1 (V2) while, application of 100 % organics equivalent to RDP (50 % FYM and 50 % vermicompost) in combination with either of foliar application with Panchagavya @ 3 % or Biodigester @ 10 % or cow urine spray @ 10 % at flowering and 15 days after flowering can be used for obtaining higher seed yield in Kabuli chickpea varieties.


2012 ◽  
Vol 58 (No. 4) ◽  
pp. 181-185 ◽  
Author(s):  
A. Bano ◽  
F. Ullah ◽  
A. Nosheen

The effect of drought stress and abscisic acid (ABA) applied at tillering stage (55 days after sowing) was compared in 2 wheat cultivars differing in drought tolerance. The activities of superoxide dismutase (SOD) and peroxidase (POD) and contents of endogenous ABA in plants were measured at 3 days of drought stress in cv. Chakwal-97 (drought tolerant) and cv. Punjab-96 (drought susceptible). ABA was applied at 10<sup>&ndash;6</sup> mol/L as presowing seed treatment for 18 h. Drought tolerant cultivar has a more efficient mechanism to scavenge reactive oxygen species as shown by a significant increase in the activity of antioxidant enzyme SOD. Under drought stress, ABA significantly increased the activities of SOD and POD, showing a significant decline on rewatering. The relative water content was significantly increased by ABA priming under drought stress in both wheat cultivars. The sensitive cultivar exhibiting lower endogenous ABA content was more responsive to ABA priming. On rewatering, the magnitude of recovery from drought stress was greater in tolerant cultivar. ABA was highly effective in improving grain weight of tolerant cultivar under drought stress. &nbsp;


2007 ◽  
Vol 17 (2) ◽  
pp. 81-90 ◽  
Author(s):  
Nicolás Gualano ◽  
Fernando Carrari ◽  
María Verónica Rodríguez ◽  
Laura Pérez-Flores ◽  
Rodolfo Sánchez ◽  
...  

AbstractIn the work reported in this paper, we attempted to elucidate the nature of the different abscisic acid (ABA) sensitivities presented by developing embryos from sorghum [Sorghum bicolor (L.) Moench] lines with contrasting pre-harvest sprouting (PHS) behaviour (Redland B2, susceptible; IS 9530, resistant). We explored two different hypotheses for a possible mechanism: (1) a different functionality of the ABA signalling pathway, and (2) a different rate of ABA degradation/conjugation in the apoplast of embryos from these genotypes. To assess the first possibility, we used an ABA-responsive gene (Rab17) as a reporter of changes in endogenous ABA content, which were artificially induced in embryos from both genotypes by means of fluridone application immediately after anthesis, to reduce ABA content, and embryo incubation in the presence of ABA. A defect in ABA signalling should be seen as a level of Rab17 expression that is independent of endogenous ABA content. For testing the second possibility at two stages of development, embryos from both lines were isolated and incubated in water for different periods. ABA concentrations in embryos and the incubation media were quantified through radioimmunoassay. In contrast to our findings for the resistant IS 9530 line, Rab17 expression did not respond to changes in ABA levels in sensitive Redland B2 embryos. The ABA degradation/conjugation rates in embryos and incubation media did not show clear differences between sorghum lines for any of the developmental stages analysed. These results suggest that a disruption in the ABA signal transduction pathway in Redland B2 underlies the low ABA sensitivity shown by embryos from this line.


2007 ◽  
Vol 17 (3) ◽  
pp. 165-174 ◽  
Author(s):  
Carlos O. Gosparini ◽  
Hector A. Busilacchi ◽  
Paolo Vernieri ◽  
Eligio N. Morandi

AbstractThe germination of developing seeds is very uncommon and is generally associated with deficiencies in abscisic acid (ABA) synthesis or sensitivity. This paper examines the quantitative relationship between the inhibition of precocious germination and endogenous ABA in the embryonic axis (ABAa) of hydrated soybean [Glycine max (L.) Merr.] seeds, isolated after the completion of histodifferentiation and before the beginning of dehydration, as well as the magnitude and evolution of axis sensitivity to endogenous ABA during that period. Developing seeds harvested at 25, 30, 35, 40 and 45 d after anthesis (DAA) were subjected to incubation or washing to induce changes in ABA content. ABA content was measured by radioimmunoassay, using a monoclonal antibody against free ABA. Germinability was measured as the time to 50% germination (t50). Washing and incubation induced eight- and twofold increases, respectively, in the rate of ABAa decline compared with the in planta ABAa decline. The threshold ABAa for inhibition of precocious germination (ABAc) increased slightly from 25 to 40 DAA [1.15–1.66 μg ABA (g DW)− 1]. This contrasted with the substantial decline in ABAa [10.90–2.07 μg ABA (g DW)− 1] during the same period, and indicated that sensitivity to endogenous ABA of hydrated seeds was initially high and diminished slowly during development. The relationship between (ABAa–ABAc) and t50 was linear for immature seeds incubated before and after washing. Below the ABAc, there were no differences in the t50 of 25–45 DAA seeds. The ABAa contribution to the control of precocious soybean seed germination was evident, although other potentially interacting factors were also present.


1969 ◽  
Vol 51 (1) ◽  
pp. 46-54
Author(s):  
Alex G. Alexander

Immature sugarcane was treated with chemical additives to determine whether significant and predictable changes could be induced in enzyme behavior. All plants were grown in sand culture with controlled nutrient supply. One group received foliar application of ascorbic acid, cysteine, hydroxylamine and cyanide; the other group received silicon, iron, and cyanide as nutrient-solution supplements. Enzymes assayed included acid phosphatases, invertase, amylase, peroxidase, and tyrosinase (polyphenoloxidase). Each of the chemicals tested was known to affect one or more enzymes in vitro. Plants receiving 1,000 p.p.m. of cyanide as a foliar spray increased sucrose in leaves and meristem within 3 days. All enzymes measured were suppressed by CN. Amylase was markedly stimulated by 50 and 1,000 p.p.m. of cysteine. All the enzymes assayed were moderately stimulated by 50 p.p.m. of cysteine, whereas 1,000 p.p.m. caused general suppression. Plants receiving 200 p.p.m. of cyanide as a nutrient-solution supplement were greatly stunted and revealed low sugar content of leaf and meristem tissues. Tyrosinase was about 3 times more active in high-cyanide plants than in controls. Silicon added to nutrient solutions at rates of 20 and 200 p.p.m. greatly retarded invertase and tyrosinase. This confirms similar observations recorded earlier, and it is suggested that enzyme inhibition is a physiological function of silicon in sugarcane. Iron added to nutrient solutions at the rate of 10 p.p.m. caused general enzyme suppression, particularly with regard to meristem peroxidase and invertase. Significance of enzyme regulation in living cane is briefly discussed.


Author(s):  
Wifak A Al-Kaisy ◽  
Sahar F Mahadi

A field experiment was conducted at botanical garden of Department of Biology, College of Education for Pure Science (Ibn Al-Haitham), University of Baghdad, during the growth winter season of 2016-2017 to study the effect of different concentrations (0, 10, 20) mg.L-1 of abscisic acid and (0, 50, 100, 150) mg.L-1 of vitamin C and their interaction on some plant hormones of pea plant (Pisum sativum L.). The results showed that ABA 20 mg.L-1 decreased IAA about 27.44%, GA3 about 19.73% and Kinetin 15.37% while vitamin C with 150 mg.L-1 increased IAA 27.43%, GA3 45.31% and Kinetin 58.53%, but ABA increased about 23.01% for ABA and 34.93% for vitamin C compared with control plants. The interaction between them is significant for four plant hormones.


Author(s):  
J. Sakthi ◽  
K. Kaleeswari ◽  
Karthika S Kumar ◽  
K. Nirosha ◽  
K. Ramya ◽  
...  

Field experiment was conducted at farmer field in kadukkarai village, Kanyakumari during February 2021 – April 2021 to evaluate the Effect of foliar nutrition for maximizing the productivity of rice fallow blackgram (Vigna mungo (L). Hepper). Nine treatments were tested in randomized block design with three replications. Among the treatments, application of RDF + Foliar spray of 1% 19:19:19 on 15 DAS + Foliar spray of 1% 12: 61:0 30 DAS + Foliar spray of 1% 13:0:45 on 45 DAS significantly recorded highest grain yield (723 kg ha-1) and haulm yield (2320 kg ha-1). However, the highest gross return (Rs.53, 955), net return (Rs.41, 305) and BC ratio (3.27) were recorded the foliar spray of 1% 19:19:19 on 15 DAS + Foliar spray of 1% 12: 61:0 30 DAS + Foliar spray of 1% 13:0:45 on 45 DAS.


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