Use of plant stimulants in cotton during germination

Cotton is widely cultivated in Brazil, and to guarantee the success of crops one of the main factors is the implementation of a flawless stand and for this it is essential to know the metabolic processes involved in the degradation of reserves during germination, as these can affect the initial development of seedlings causing losses in the initial establishment of the crop.

As a way to accelerate and improve seed germination and also promote initial plant growth, the use of plant stimulants is recommended. With this in mind, the work aimed to evaluate the effect of applying a plant stimulant on the mobilization of cotton reserves during germination.

About the experiment 

The experiment was conducted in the seed laboratory of Faculdade Arnaldo Horácio Ferreira – FAAHF, during the month of June 2019. The experimental design used was completely randomized, in a 2 x 3 factorial scheme, corresponding to the presence and absence of stimulate® and the 3 evaluation periods, with four repetitions of 20 seeds.

The seeds were treated with stimulate 20 mL/kg, then they were placed to germinate on a roll of germitest paper, moistened with 2,5 x the dry weight of the paper, the seeds were dispersed on the paper with the hilum facing downwards and placed in the position vertically in a germination chamber at 25 ºC.

Seedling development was evaluated every 2 days, for 6 days, totaling 3 evaluations being carried out on 10 seedlings per repetition. To evaluate development, the seed coat was removed, the cotyledon was separated from the embryonic axis, and the length of the embryonic axis was measured. Then, the cotyledons and the embryonic axis were placed separately in paper bags and taken to the forced ventilation oven at 65 ºC for 72 hours, being subsequently weighed on an analytical balance, to determine the seedling dry mass (MSP) and dry mass of cotyledons (MSC). The collected data were subjected to analysis of variance and the means were compared with each other using the 5% Tukey test.

Application analytics 

There was no interaction between the factors for any of the variables evaluated. Seedlings from seeds treated with stimulate (8,8 cm) showed higher growth than seedlings from control seeds (6,99 cm) (Table 1). 

For MSP there was no significant difference between treatments, however there was an increase in MSP during the days evaluated, with an average of 0,007 to 0,014 g (Table 2). As for MSC, the seeds treated with stimulate were lower than the control, where both showed a decrease in MSC over the days evaluated, with an average of 0,043 on the first day and 0,024 g on the last day of evaluation (Table 2).  

It can be observed that there was a reduction in the dry mass of the cotyledons and an increase in the total dry mass of the seedling. These reductions demonstrate the mobilization of reserve compounds from the cotyledons and their translocation to other organs, as the reduction in cotyledon dry mass reflects the increase in seedling dry mass production.

These transports were greater in seeds treated with stimulate as they showed a greater reduction in MSC and an increase in MSP, generating larger seedlings than those not treated.

CONCLUSION

The use of stimulate in the treatment of cotton seeds positively influences the mobilization of cotyledon reserves, providing greater seedling growth. 

José Fontana Santos Brito, Juliano Alves da Cruz and Juliane Karsten, UNIFAAHF – Centro Universitário Arnaldo Horacio Ferreira; Ricardo de Andrade Silva, FMC - FMC Química do Brasil LTDA