growers know
In plant predators, the
effects of MeJa can
range from an unpleasant
digestive issue to causing
cannibalistic tendencies.”
plants succumbed to predation by fungal gnat larvae. After
those same species of plants were treated with naturally
occurring levels of MeJa, mortality rates dropped down to
only 12 per cent. The researchers then wanted to determine
if the MeJa itself was what killed plant predators. It had
no effect on the fungal gnat larvae when used alone. So, it
is critical the plants absorb MeJa in order to develop and
use its own defenses to fend off invading insects. Further,
this study found that it was possible to block the wound-
signaling abilities of MeJa in plants with an antisense gene,
which can occur in mutant plants.
This study declared, “Jasmonate is both necessary and suffi-
cient for plant defense.”
The ability to protect a plant from predators is not the only
defense offered by MeJa. Other research has shown that foliar
sprays of MeJa have antibacterial effects on plants. More
research is still needed to draw positive conclusions, but it
seems that the introduction of MeJa through plant stomata
puts a plant on “high alert” status that can increase its ability
to resist the effects of certain diseases.
A 1998 joint Canadian and American study looked at the
disease response of plants affected with the fungal disease
pythium. It found that JA, a component of MeJa, activated the
genes that act in defense of plant pathogens as opposed to
those that aid in the defense against insects. A particular
defensive gene in the plant species Arabidopsis essentially
created a protein with anti-fungal properties is equally
“activated” by exposure to either a pathogen directly or
by the presence of JA. Methyl jasmonate along with the
compound ethylene (more on this in the next section) create
a synergy in certain gene families within plants that create
proteins for defense against diseases. Similar to the previ-
ously mentioned study, mutant plants that did not have
natural levels of MeJa were highly susceptible to succumb-
ing from pythium and those plants that either naturally
had the ability to produce it or were given foliar MeJa treat-
ments were able to successfully fight off or be less suscep-
tible to the effects of the pathogen. Even more similar is
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grow cycle