الفهرس 
Effect of saline conditions on rootstocksOnly 14 pages are availabe for public view
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Abstract
In this work two field experiments were carried out during a three
successive seasons of 2015/2016 , 2016/2017 and 2017/2018 to evaluate
the physiological response of foliar application of some antioxidants
(salicylic and ascorbic acids) on Valencia orange and Chinese tangerine
young trees grown under irrigation with saline water. The two Citrus
varieties, Valencia orange (V. O) Citrus sinensis.L. osbeck and Chinese
(Ponkan) mandarin (Citrus reticulate ) were budded on three citrus
rootstocks namely sour orange (Citrus aurantum, mion) ,Volkamer
lemon (V. L) (Citrus volkameriana, Tem) and X639 hybrid between
(Citrus reticulate × Ponicurus trifoliata).
As for Valencia orange, results showed that Volkamer lemon
rootstock gave the highest values of most studied characters of vegetative
growth (height increment percentage, stem diameter increment
percentage, number of leaves increment percentage and leaf area cm2).As
compared with other studied rootstocks with exception that with
exception that salicylic acid was effective also on stem diameter and
leaves number increment. In addition, the results revealed that, higher
growth parameters were recorded by the interaction between Volkamer
lemon rootstock and ascorbic acid at concentration of 800 ppm. As for
physiological and biochemical constitutes (relative water content , proline
content , protein content , total antioxidant capacity , carbohydrates
content , chlorophyll a, chlorophyll b and carotenoids.) Volkamer lemon
rootstock achieved the higher values most of the previous characters in
combination with ascorbic acid and salicylic acid at 600 to 800 ppm with
exception that X639 rootstock which achieved the higher carbohydrates
and proline content, while Volkamer lemon achieved the least values. On
the other hand Valencia orange budded on Volkamer lemon rootstock
recorded the higher chemical content (macro elements: nitrogen,
phosphorus, potassium ,calcium and micro elements ; zinc and
magnesium) in combination with ascorbic acid and salicylic acid at 600 to
800 ppm , with exception that Sour orange accumulated the higher
Magnesium content, on the other hand Volkamer lemon rootstock
accumulated under saline conditions higher content of micro elements
iron, zinc and manganese, the values increased gradually by treatment of
antioxidants from 0 to 800 ppm concentrations. salicylic acid was more
effective in concentration than ascorbic acid . As for endogenous
hormones content Volkamer lemon rootstock achieved the higher
hormonal content (indole acetic IAA acid and Gibberlinne GA) and the
lower abscisc acid ABA, on the other hand both salicylic and ascorbic
acids at 800 ppm in combination with Volkamer lemon rootstock reduce
the harmful effects of salinity stress on Leaf anatomical structure
compared with the control.
As for Chinese tangerine Results showed that, Volkamer lemon
rootstock surpassed Sour orange and X639 rootstocks under saline
conditions, the highest incremental percentage young tree height, stem
diameter, number of leaves per shoot and leaf area were registered by
Chinese tangerine scion budded on Volkamer lemon rootstock. Among
selected antioxidants, ascorbic acid at the concentrations of 800 ppm
recorded the highest significant values for vegetative growth parameters
and surpassed salicylic acid. As for physiological and biochemical
constitutes (relative water content , proline content , protein content , total
antioxidant capacity, carbohydrates content , chlorophyll a, chlorophyll b
and carotenoids.) Volkamer lemon rootstock achieved the higher values
most of the those characters in combination with ascorbic acid and
salicylic acid at 600 to 800 ppm with exception that X639 rootstock
which achieved the higher carbohydrates and proline content, while
Volkamer lemon achieved the least values.
Also Chinese mandarin scion budded on Volkamer lemon
accumulated the higher concentrations of nitrogen (N), phosphorus (P),
magnesium (Mg), and chloride (Cl-) and the lowest concentration of
sodium (Na+). Chinese mandarin scion budded on sour orange rootstock
accumulated the highest concentrations of potassium (K) while Chinese
tangerine scion budded on X639 accumulated the highest concentrations
of sodium (Na). In addition, the results revealed that, higher growth
parameters were recorded by the interaction between Volkamer lemon
rootstock and ascorbic acid at concentration of 800 ppm.The studied
rootstocks exhibited insignificant differences in Fe concentration, while
Volkamer lemon rootstock exhibited the higher zn and mn concentration
under saline conditions .Volkamer lemon rootstock recorded the higher
content of zn and mn when interacted with 800 ppm of salicylic acid for
zn content and 800 ppm of ascorbic acid for Mn content .In this respect
Sour orange registered the higher Fe concentration by 600 ppm of
salicylic acid. As for endogenous hormones content Volkamer lemon
rootstock achieved the higher hormonal content (indole acetic IAA acid
and Gibberlinne GA) and the lower abscisc acid ABA, on the other hand
the same rootstock reduce the harmful effects of salinity of the anatomical
structure of leaves. .
Key words: Rootstocks, antioxidants, saline conditions.