158
Subtle Agroecologies
the sugar company ‘Archimedes Colina’, Mabay, Bayamo, Granma, Cuba (using the methodology
of the National Institute of Sugarcane Research) (INICA, 2002).
Sixty stalk segments of one-bud sets of each crop were irradiated with laser beams using medical
laser or He-Ne, wavelength 660 nm, red light power density of 360 mW.cm -2 . The laser treatments
consisted of two irradiation times to the buds: 10 seconds (30 one-bud sets) and 20 seconds (30
one-bud sets), with a control treatment consisting of 30 one-bud sets that did not receive laser treatment. The buds were placed in nylon containers that are commonly used to market milk or yogurt
in Cuba, with a substrate consisting of 50% soil and 50% cow manure. The percentage of vegetative
bud break in each species was determined after 15 and 30 days.
In both crops, the variable was checked to see whether it met the criteria for a variance analysis, the normal distribution of data through the Shapiro–Wilk test, using InfoStat 2019 (Di Rienzo
et al., 2019), and the homogeneity of variances using the Levene test (Minitab, 2013). The data were
found to be distributed normally, and their variances were homogeneous. The data were statistically
processed through a fxed-effect simple-classifcation variance analysis, with a two-factor treatment
of 2 × 2. Factor 1 corresponded to the laser-beam treatment with two exposure times: 10 and 20 seconds; and factor 2 corresponded to the two different times when the evaluations were performed:
15 and 30 days. The multiple comparisons of the mean treatments were made using Tukey’s test at
5.0% probability. The mean of each treatment and its standard error were represented in a bar chart
(see Figure 14.1).
RESULTS AND DISCUSSION
A signifcant response to the laser applications was found for vegetative bud breaks in mulberry.
The best response was found to the laser applications lasting 10 seconds, with 76.7% of vegetative bud break, compared to 63.3% with a laser application lasting 20 seconds, and 60.6% bud
break (Figure 14.1a) in the control treatment (with no laser application). No signifcant differences
were found between the two time intervals evaluated (Figure 14.1b), indicating that during this
period there were no morphological qualitative changes in the development of new mulberry shoots
through the effect of laser beams (Figure14.1).
When the percentages of vegetative bud breaks for the two laser exposure time periods were
combined and compared to the control, signifcant differences in the interactions between these
two treatments were found (Figure 14.1c). The higher percentages of budding occurred in buds that
received laser treatments for a space of 10 seconds, percentages that increased as the days passed.
The lowest percentages were obtained in the control at 15 days, with an increase at 30 days, while
with 20 seconds of laser exposure, intermediate results were achieved in both evaluations (after 15
and 30 days)
The same procedure was repeated on the sugarcane (variety C90-469), and produced similar
results to the mulberry (Figure 14.2). The highest percentage of vegetative bud break, at 85.6%, was
with the application of the laser for 10 seconds, followed by the control treatment with 64.4%, while
the lowest bud break was the application of the laser for 20 seconds, with 58.9% (although there was
no signifcant difference between the latter two). As with the mulberry experiment, no signifcant
time factor effects were found.
EFFECTS OF LOW-POWER LASER BIOTECHNOLOGY PRETREATMENT
UNDER FLOODING STRESS IN MULBERRY AND SUGARCANE
MATERIALS AND METHODS
For this experiment, plants from the laser treatment that resulted in the best bud break – exposure
for 10 seconds and after 30 days– were used, together with a control. Forty cuttings were prepared
(20 of mulberry cuttings and 20 of sugarcane) from the frst experiment that were exposed to
Subtle Agroecologies
the sugar company ‘Archimedes Colina’, Mabay, Bayamo, Granma, Cuba (using the methodology
of the National Institute of Sugarcane Research) (INICA, 2002).
Sixty stalk segments of one-bud sets of each crop were irradiated with laser beams using medical
laser or He-Ne, wavelength 660 nm, red light power density of 360 mW.cm -2 . The laser treatments
consisted of two irradiation times to the buds: 10 seconds (30 one-bud sets) and 20 seconds (30
one-bud sets), with a control treatment consisting of 30 one-bud sets that did not receive laser treatment. The buds were placed in nylon containers that are commonly used to market milk or yogurt
in Cuba, with a substrate consisting of 50% soil and 50% cow manure. The percentage of vegetative
bud break in each species was determined after 15 and 30 days.
In both crops, the variable was checked to see whether it met the criteria for a variance analysis, the normal distribution of data through the Shapiro–Wilk test, using InfoStat 2019 (Di Rienzo
et al., 2019), and the homogeneity of variances using the Levene test (Minitab, 2013). The data were
found to be distributed normally, and their variances were homogeneous. The data were statistically
processed through a fxed-effect simple-classifcation variance analysis, with a two-factor treatment
of 2 × 2. Factor 1 corresponded to the laser-beam treatment with two exposure times: 10 and 20 seconds; and factor 2 corresponded to the two different times when the evaluations were performed:
15 and 30 days. The multiple comparisons of the mean treatments were made using Tukey’s test at
5.0% probability. The mean of each treatment and its standard error were represented in a bar chart
(see Figure 14.1).
RESULTS AND DISCUSSION
A signifcant response to the laser applications was found for vegetative bud breaks in mulberry.
The best response was found to the laser applications lasting 10 seconds, with 76.7% of vegetative bud break, compared to 63.3% with a laser application lasting 20 seconds, and 60.6% bud
break (Figure 14.1a) in the control treatment (with no laser application). No signifcant differences
were found between the two time intervals evaluated (Figure 14.1b), indicating that during this
period there were no morphological qualitative changes in the development of new mulberry shoots
through the effect of laser beams (Figure14.1).
When the percentages of vegetative bud breaks for the two laser exposure time periods were
combined and compared to the control, signifcant differences in the interactions between these
two treatments were found (Figure 14.1c). The higher percentages of budding occurred in buds that
received laser treatments for a space of 10 seconds, percentages that increased as the days passed.
The lowest percentages were obtained in the control at 15 days, with an increase at 30 days, while
with 20 seconds of laser exposure, intermediate results were achieved in both evaluations (after 15
and 30 days)
The same procedure was repeated on the sugarcane (variety C90-469), and produced similar
results to the mulberry (Figure 14.2). The highest percentage of vegetative bud break, at 85.6%, was
with the application of the laser for 10 seconds, followed by the control treatment with 64.4%, while
the lowest bud break was the application of the laser for 20 seconds, with 58.9% (although there was
no signifcant difference between the latter two). As with the mulberry experiment, no signifcant
time factor effects were found.
EFFECTS OF LOW-POWER LASER BIOTECHNOLOGY PRETREATMENT
UNDER FLOODING STRESS IN MULBERRY AND SUGARCANE
MATERIALS AND METHODS
For this experiment, plants from the laser treatment that resulted in the best bud break – exposure
for 10 seconds and after 30 days– were used, together with a control. Forty cuttings were prepared
(20 of mulberry cuttings and 20 of sugarcane) from the frst experiment that were exposed to