scholarly journals Water stress in germination, growth and development of coffee cultivars

2018 ◽  
Vol 40 (1) ◽  
pp. 82-89 ◽  
Author(s):  
Julieta Andréa Silva de Almeida ◽  
Mary Túlia Vargas Lobato Guedes de Azevedo ◽  
Marcus Vinicius Salomon ◽  
Priscila Fratin Medina

Abstract: The aim of this study was to evaluate the effect of water stress on the germination of Coffea arabica seeds and the growth and development of plants from these seeds. Seeds of the cultivars Bourbon Vermelho, Mundo Novo, and BA-10 were placed to germinate in the dark at 30 ºC in the presence and absence of 100 g/L of polyethylene glycol 6000. The water stress applied delayed the beginning of seed germination by seven days in relation to seeds of the control, which had achieved responses of up to 50%, but there were no differences between the treatments at the end of the experiment. Furthermore, the length of the primary root in seeds germinated under water stress was less than in the control treatment, especially for the cultivar Mundo Novo. Plants of the cultivars Bourbon Vermelho and Mundo Novo developed from seeds previously germinated under water stress exhibited reduced height and fewer leaf pairs than those from the control, whereas ‘BA-10’ responded in a similar way in both treatments. Thus, the cultivars Bourbon Vermelho and Mundo Novo were more sensitive to the water stress applied in the germination phase than ‘BA-10’.

2019 ◽  
Vol 10 (09) ◽  
pp. 1240-1254
Author(s):  
Manlé Tokpapon Eliane ◽  
Kouassi Kan Modeste ◽  
Soumahoro Brahima André ◽  
Koffi Kouablan Edmond ◽  
Koné Mongomaké

2019 ◽  
Vol 9 (4) ◽  
pp. 603-612
Author(s):  
Larissa De Oliveira Fontes ◽  
Alexandre Bosco de Oliveira ◽  
Eneas Gomes Filho ◽  
Maria de Fátima De Queiroz Lopes ◽  
José Hamilton da Costa Filho ◽  
...  

The objective of this work was to evaluate, in two experiments, the effect of water stress and luminosity on the germinative behavior and vigor of Amaranthus deflexus L seeds. The seeds were sown in Petri dishes containing two sheets of filter paper moistened with distilled water, in the control treatment. Using this treatment-control configuration, as a standard of comparison, two assays were performed using subsamples from the same A. deflexus seed population. In the first experiment (experiment 1), solutions of polyethylene glycol 6000 (PEG 6000) were used, providing osmotic potentials of -0.3; -0.6; -0.9; -1.2 and -1.5 MPa; however, in the second trial (experiment 2) osmotic potentials of -0.1; -0.2; -0.3; -0.4 and -0.5 MPa were used. At the end of the test, the ungerminated seeds for each treatment were washed and germinated on a filter paper moistened with water. The germination and vigor of the seeds were evaluated through the first germination count, germination test, germination speed index and average germination time. The experimental design was completely randomized, in a 2 x 6 factorial scheme, totaling twelve treatments, with four replicates of 50 seeds each, in both trials. Water stress negatively affects the performance of A. deflexus seeds, reducing germination and vigor from -0.1 MPa. Seed germination was compromised by the absence of light, regardless of the applied stress levels. There was an increase in seed germination after application of the same at higher levels of water stress.


2018 ◽  
Vol 40 (1) ◽  
pp. 36-43 ◽  
Author(s):  
Ayslan Trindade Lima ◽  
Paulo Henrique de Jesus da Cunha ◽  
Bárbara França Dantas ◽  
Marcos Vinicius Meiado

Abstract: Seed hydration memory is the ability of seeds to retain biochemical and physiological changes caused by discontinuous hydration. This study aimed to determine if Senna spectabilis (DC.) H.S. Irwin & Barneby var. excelsa (Schrad.) H.S.Irwin & Barneby (Fabaceae) present seed memory and evaluate the effects of hydration and dehydration cycles (HD) on the seed germination of this species when submitted to conditions of water stress. Seeds underwent HD cycles (0, 1, 2 and 3 cycles) corresponding to the hydration times X (6 hours), Y (16 hours) and Z (24 hours), determined from the imbibition curve, with 5 hours of dehydration and submitted to water stress conditions. Germination was evaluated at 0.0, -0.1, -0.3, -0.6 and -0.9 MPa, obtained with polyethylene glycol 6000 solution. Germinability (%), mean germination time (days) and hydrotime (MPa d-1) were calculated. The seeds of S. spectabilis var. excelsa are sensitive to the low osmotic potentials tested in this study, however, when submitted to the HD cycles of 16 hours hydration (time Y), the tolerance to water stress conditions is increased. In addition, the observed benefits on the evaluated germination parameters show that S. spectabilis var. excelsa present seed hydation memory.


1969 ◽  
Vol 47 (11) ◽  
pp. 1761-1764 ◽  
Author(s):  
Merrill R. Kaufmann

The effect of nearly constant water potential on germination of citrus, sunflower, and lettuce seeds was studied. Water potential equilibration was achieved by placing soil above a cellulose acetate membrane which was in contact with a solution of polyethylene glycol-6000. Selection of solute potentials in the solution resulted in controlled water potentials in the soil over a range of 0 to −14.9 bars for citrus and 0 to −8.0 bars for sunflower and lettuce. The water stress experienced by germinating seeds in this system is largely the result of a matric effect rather than a solute effect.Citrus seeds germinated at water potentials as low as −4.7 bars and lettuce at −4.1 bars, but sunflower germinated at −8.0 bars. Sunflower germinated as rapidly at −4.1 bars as lettuce at −2.3 bars, both reaching 50% germination at about 8 days. Citrus germinated much more slowly, requiring 26 days at 0 bars.


2014 ◽  
Vol 68 (1) ◽  
pp. 39-54 ◽  
Author(s):  
Parvin Salehi Shanjani ◽  
Masoumeh Izadpanah ◽  
Mohamad Reza Mohamadpour

ABSTRACT The effects of water potential on germination were studied in 18 wild populations of three yarrow species (Achillea tenuifolia, A. vermicularis and A. filipendulina) from different bioclimatic zones in Iran. Water potential between 0 and -0.6 MPa were obtained using polyethylene glycol 6000 (PEG-6000) solutions. The study of water stress on germination showed that, regardless of the species and the populations, the lowering of the water potential reduced the capacity for germination and early seeding growth. These results indicated a strong genetic potential for drought tolerance during germination within each species. These differences in germination ability of wild populations of each species might be attributed to intraspecific variations resulting from the effects of natural selection and genetic pool background.


2021 ◽  
Vol 15 (1) ◽  
pp. 12-25
Author(s):  
Tokpapon Eliane Manlé ◽  
Kan Modeste Kouassi ◽  
Brahima André Soumahoro ◽  
Tchoa Koné ◽  
Kouablan Edmond Koffi ◽  
...  

Rainfall scarcity due to climate change is a major constraint that limits cocoa productivity in Côte d'Ivoire. This work aims to regenerate cocoa plants tolerant to water stress using in vitro methods. Staminode and petal explants of the genotypes C1, C9, C14, C15, C16, C18 and C20 were used to produce somatic embryos through two methods. Firstly, somatic embryos were induced under stressfull conditions on media containing different concentrations of polyethylene glycol (PEG) 6000 (0; 25; 50; 75; 100 and 125 g/l) and secondly; under non-stressed conditions. Somatic embryos were placed on a conversion medium in the same stress condition. The number of regenerants decreased with the increase in the concentration of PEG with all genotypes. Only genotypes C1 and C15 regenerated plantlets under water stress conditions. The sensitive genotypes C9, C14, C16, C18 and C20 have not developed plantlets on media containing PEG. The plantlets produced under water deficit conditions exhibited a reduction in stem length and leaves number and an increase in length or offset of the high number of roots. The survival rate of regenerants during acclimatization was higher on the sandsubstrate. The selected genotypes could be used in an improvement program of cocoa production.Keywords: Climate change; plant regeneration; genotype; tolerance; drought; in vitro


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