الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
This study was carried out during two consecutive seasons of 1992 and
1993 on four citrus rootstocks namely: Volkamer lemon, Mexican lime,
Cleopatra mandarin and Rangpur lime at the Experimental orchard of
Horticultural Research Institute at Giza : Selected trees for this investigation were 22-year- old, except for Volkamer lemon (8-year -old). They received regularity the normal Horticultural practices.
Hardwood cuttings were prepared from one- year- old branches.
Cuttings of about 10-12’ em long and 1-1.5 ern in diameter were prepared at
three dates namely mid-March, mid-June and mid-September. Leaves on each
cuttings were removed except only one leaf was left at the apex of cutting.
However, just before planting the cuttings were grouped into two groups as
follows: (a) First group : The basal end of the cuttings at about 5 ern was
dipped for 5 seconds in tap water ”general control” or one of indole butryic acid solutions at 2000, 4000, 6000, and 8000 PPM. (b) The second group: The basal
end of cuttings were wounded (about one inch) by making 2 incisions. The
cuttings were dipped in tap water ”control” or one of indole butyric acid solutions 2000, 4000, 6000 and 8000 PPM. The treated cuttings were immediately planted at a depth of 5 ern in plastic flats (32 em length x 25 em width x 15 cm height) filled with a mixture of sand and peat moss at 2 : I(v/v). The flats were kept for 60 days in a shade house under intermittent mist, operating during days house according to seasonal and daily weather conditions, within a range of 2.5 - 5.0 minutes between sprays and 5-15 seconds of mist duration. Thus, the study of each citrus rootstocks is considered a factorial
experiment .consisted of 30 treatments (three planting dates x five IBA
concentrations x two wounding treatments) . The treatments were arranged in a
completely randomized block design with four replicates for each treatment and
each replicate included ten cuttings . The obtained results could be summarized
as follows : 5-1- Rooting of citrus rootstock cuttings : Generally, mid-September proved to be the most appropriate time for
preparing and planting stem cutting of the studied citrus rootstocks: Volkamer
lemon, Mexican lime, Cleopatra mandarin and Rangpur lime rather than mid-
June or mid- March planting. In addition, wounding the basal ends of the
cutting, enhanced all the studied rooting parameters(rooting percentage, number of adventitious roots per cutting and root fresh and dry weight parameters).Also, dipping the basal ends of cuttings in indole butyric acid solutions at 2000, 4000, 6000 or 8000 ppm for five seconds increased the rooting ability of the
cuttings particularly, 8000 PPM IBA. Furthermore, the stimulating effect of
the studied factors (planting date, IBA and wounding was increased when they
used in combinations whether in double combination (planting date x wounding,
~ planting date x IBA or wounding x IBA) or trible combination (plating date x wounding x IBA )Conclusively, planting citrus rootstocks cuttings in mid-September after
wounding and treating with IBA at 8000 ppm gave the highest rooting
percentage 5-2 Chemical study : 5-2-l-Total soluble indoles and phenols
In general, planting date had significant effect on totals indoles and
phenols of cuttings . Shortly, planting Volkamer lemon, Mexican lime,
Cleopatra mandarin and Rangpur lime cuttings in mid- September increased
cutting content total soluble indoles and decreased its content of total soluble phenols as compared with those planted either in mid-March or mid-June.
5-2-2- Total carbohydrates and nitrogen content. The highest total carbohydrates and nitrogen content were shown in Volkamer lemon cuttings prepared and planted in mid-September followed by
mid- March planting. While, those planted in mid-June showed be the lowest
values in this respect. Generally, total carbohydrates and nitrogen content of Mexican lime, Cleopatra mandarin and Rangpur lime cuttings took similar trend to that ofVolkamer lemon.
Anatomical study : Histological study reveals that the preformed root initials were noticed in
the cortex of the four studied citrus rootstocks under investigation. Root initials were raised from cambuim zone. Moreover, cambium was activated in all IBAtreated cuttings, particularly, when IBA was supplemented by wounding
treatment. Generally, the results showed that treating the wounded cuttings ofVolkamer
lemon, Mexican lime and Cleopatra mandarin as well as Rangpur lime with
IBA at 4000,6000 and 8000 PPM improved the studied rooting parameters. On
the other hand, treating wounded cuttings with IBA and planting in mid-
September proved to be the most effective treatments in enhancing rooting parameters (rooting percentage, number of roots per cutting fresh and dry weight of roots per cutting) as compared with the analogous ones planted in mid-March or mid-June.