الفهرس 
Material and methodsOnly 14 pages are availabe for public view
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Abstract
Pot experiments were carried out at the Experimental Station of the Agricultural Botany Department, Faculty of Agriculture Moshtohor, Zagazig University during 1997/98 and 1998/1999 seasons to study the effect of Gibberellic acid (GA3), Yeast extract preparation (IT) and Naphthalene acetic acid (NAA) preceded with or without cold stratification on Magnolia seeds at germination and seedling growth. Magnolia seeds
were divided into two groups.
First group, i.e. stratified seeds:
Seeds were stratified for 2 months at 5 ± 1°C. Then
seeds were treated as the following:
1-Soaking in 50 ppm GA3
2-Soaking in 100 ppm GA3
3-Soaking in Yeast extract (YE)50 m1/1.
4-Soaking in Yeast extract (YE)100 ml/1.
5-Soaking in 50 ppm Naphthalene acetic acid (NAA).
6-Soaking in 100 ppm Naphthalene acetic acid (NAA).
7-Soaking in distilled water as control treatment.
- Treated seeds:
In this experiment seeds were only soaked in the assigned treatments of the two growth regulators (GA3 and NAA) and yeast extract (YE) with the concentrations as in case of first group but with previous stratification, so
treatments were the following.1-Soaking in 50 ppm GA3
2-Soaking in 100 ppm GA3
3-Soaking in Yeast extract (YE)50 m1/1.
4-Soaking in Yeast extract (YE)100 ml/l.
5-Soaking in 50 ppm Naphthalene acetic acid (NAA).
6-Soaking in 100 ppm Naphthalene acetic acid (NAA).
7-Soaking in distilled water as control treatment.
Seeds of different applied treatments were soaked for 24h. Then seeds of different treatments were sown in pots 20 cm in diameter until the time of eight months. After that, emerged seedlings were transplanted into pots of 30 cm
in diameter.
The following data were recorded:
I- Seedling appearance:
- The highest percentage and rate of emerged seedlings were 48% with YE 50 ml in case of unstratified seeds. While, GA3 at 100 ppm ranked the second followed by NAA treatment meanwhile control treatment gave the lowest values in this respect.
On the other hand, in case of stratified seed NAA at 50 ppm exhibited the highest values (68 %) of emerged seedling followed by GA3 at 100 ppm (56%), while, 50 m1/1. YE gave the highest rate of seedling emergence in the two
seasons under study.II- Seedling growth:
1- during 6, 7 & 8 months of seedling age:
a- Unstratified seeds:
The treatment of GA3 at 100 ppm gave the highest plant high, leaves number and leaf area as well, while, YE at 50 m1/1. ranked the second followed the other treatment in 1997/1998 season yet, in 1998/1999 season YE gave the highest plant high, meanwhile, NAA at 25 ppm gave the highest leaf area.
b-Stratified seeds:
YE at 100 ml/l. gave the highest hypocotyl and length, yet GA3 at 50 ppm gave the highest plant height, meanwhile, greatest leaf area was existed in case of 50 ml/1.
YE.
2-During 18 months of seedling age:
Beside the previous estimated growth characters; the root characters were also estimated at 18 months of plant
age.
a: Plants grown up from unstratified seeds.
YE treatments gave the highest roots, stems and leaves fresh weight followed by GA3, NAA in descending order. Meanwhile, the lowest values of the growth aspects were existed in case of untreated plants.
Also, yeast treatment gave the highest dry weight comparing either with the other treatment or those of the
controls.In addition, YE treatment’ exhibited the highest activity regarding dry mater distribution in different plant
organs.
b: Plants grown up from stratified seeds:
It is the same as in case of plants grown up from
unstratifid seeds, YE gave the highest values in case of those plants grown up from stratified seeds concerning most of estimated characters.
III-Chemical analysis:
a:Chloroplast pigments: different applied
treatments at the age of 18 months showed obvious increase
of chloroplast pigments in leaves of treated Magnolia plants.
b:NPK content: the treatment of growth regulators
preceded with stratification treatment increased NPK treatment in different Magnolia organs at 18 months after sowing more than in case of stratification as a sample
treatment.
c:Total carbohydrate: it could be concluded that
each of stratification treatment alone or growth regulators preceded with stratification nearly gave the same level of total carbohydrates in different plant organs despite that
slight increase in growth regulators treatments.
d:Regarding sugars content: the growth regulators
preceded with stratification treatment increased the sugar content more than in case of stratification treatment alone.Generally YE at 50 and 100 m1/1. as seed soaking material preceded with stratification of Magnolia seeds could be considered of economic values in improving of seed germination and also enhancing of seedling growth.