الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
 |  | from | 151 |  |  |
| | | from | 151 | | |
Abstract
A factorial experiment 8 X 3 was conducted in split plot design on potted Codiaeum variegatum L. plant aiming to examine to what extant plant growth regulators or preservative solutions can maintenance plant quality during transportation and storage under cold conditions. Eight plant growth regulators and preservative solutions were tested as foliar spray before cold storage beginning; i.e., 1- Distilled water (control), 2- Benzyladenine (BA) at 10 ppm, 3- Naphthalene acetic acid (NAA) at 25 ppm, 4- Gibberellic acid (GA3) at 25 ppm, 5- Silver thiosulphate (STS) at 1:4 mM, 6- Glutathione (GSH) at 100 ppm, 7- Sodium nitroprusside (SNP) at 100 ppm or 8- BA 10 ppm + STS at 1:4 mM. Cold storage was extended up to 20 days, and plant quality was evaluated after 0, 10 and 20 days of storage. Cold storage exhibited negative effects on croton quality, since it caused reductions in leaf tensile strength and leaf hardness and in leaf tissue contents of chlorophyll a, b and total chlorophyll (a+b) as well as total carbohydrates. Simultaneously, cold storage increased leaf abscission and leaf chlorosis. These adverse effects were significantly increased with increasing storage period up to 20 days. Sprayed croton plants with BA and STS each alone or together (BA+STS), in general, recorded significant enhancements on plant quality comparing to the other tested substances. These treatments significantly increased leaf No/ plant, leaf tensile strength and leaf hardness as well as leaf tissue contents of chlorophyll and total carbohydrates, but significantly decreased leaf carotenoids content as compare to plants treated with the other growth substances. When growth substances interacted with cold storage periods, spraying croton plants with BA, STS or (BA+STS) prior to cold storage maintained plant quality during cold conditions, since after 10 or 20 days of cold storage periods, sprayed plants with BA, STS or (BA+STS) recorded the highest values of leaves No per plant; leaf tensile strength; leaf hardness; leaf tissue contents of chlorophyll a, b and total chlorophyll (a+b); and total carbohydrates as compare to plants subjected to the other interaction treatments. Studying interrelationships between plant quality characteristics exhibited significant positive correlations between each of leaves number per plant, leaf tensile strength, leaf hardness and leaf contents of chlorophylls and total carbohydrates. While, correlations between carotenoids and anthocyanin on one hand and leaf tensile strength and hardness as well as chlorophyll a, b and a+b on the other hand were significant and negative. In conclusion, spraying potted croton plant with BA at 10 ppm + STS at 1:4 mM twice prior to cold storage may be practical application for reducing the adverse effects of cold conditions on croton quality up to 20 days of storage.