The role of Trace Elements in Oxidative Hypothesis during Aging of Mung bean (Phaseolus aureus) Cuttings via Indole acetic (IAA) level.

الملخص

Naturally occurring auxin (IAA) was measured spectrophotometrically as
indicator for oxidative processes that occurs during ageing phenomenon, in terms of
rooting response of mung bean cuttings.
According to oxidative hypothesis fresh and aged cuttings as well as stock
plants were supplied with nutrient solutions that are associated with anti-oxidant
defense mechanisms, to investigate their effects in suppression of oxidative stress that
accompanied aging phenomenon. The data revealed the followings:-
a) A decline in rooting response of aged cuttings (held in d/H2O for 3 days) were
taken from seedlings grown in Hoagland solution compared to fresh cuttings, with
a percentage of decline equal to 11.8% in presence of NAA, 10-4 M and 30.8% in
its absence. This coincided with the decline of IAA level in aged cuttings
compared to fresh cuttings, and was attributed to oxidative processes that occurs
during ageing.
b) A decline in rooting response of aged cuttings in d/H2O (supplied with auxin)
taken from seedlings grown in Hoagland solutions lacking for B or Fe, compared
to control(complete Hoagland solution).

c) Significant increase in rooting response of cuttings aged in d/H2O (not supplied
with auxin) taken from seedlings grown in Hoagland solution lacking for Mn or B.
d) Increase in rooting response of fresh cuttings treated with low concentration of
SeO2 (0.001-10 ppm).
e) Increase in rooting response of cuttings aged in different strengths of complete,
modified nutrient solution (CMNS), except the case of CMNS (SeO2=1 ppm).
This confirmed the role of selenium as anti-oxidant in defense mechanisms
occurring in cuttings during ageing.
f) Increase in rootings response of cuttings aged in d/H2O (not supplied with auxin),
taken from seedlings grown in CMNS lacking for boron ( In this case, B
substituted by Se).
g) Decrease in rooting response of cuttings taken from seedlings grown in d/H2O for
(10) days, and aged in CMNS (Half strength) lacking for Mn or group of elements
(Mn, Zn, and Se). The discussion was focused on the importance of trace elements in their resistance to the damage that resulted by oxidative processes, occurring
during aging.