EFFECT OF SOME TREATMENTS ON VEGETATIVE PROPAGATION OF SOME POPLAR SPECIES

Abstract

The present study was carried out at the nursery of Forestry Department. Horticulture Research Institute, Giza in two successive seasons 2000 and 2001, ' aimed to define the optimal date for taking stem cutting, effect of cold storage and the effect of growth regulator at different concentrations on rooting of three poplar species Populus nigra, P. alba and P. euramericana. The studied three populus species differ in response to investigated treatments, that populus nigra consider easy to root, stem cuttings had extended time for planting from 15" Feb. to 8" March, also the interaction between 250 ppm ofIBA concentration with 1 March planting date maximizing rooted stem cutting % while P. euramericana taken the second order that, IBA at the lowest concentration (250 ppm) was effective in improving rooted cutting, had definite time for stem cutting plantation (22" Feb.)and the interaction between 500 ppm IBA with 15" Feb. planting date and 250 ppm IBA with 22" Feb. planting date treatments, respectively were more effective in rooting ability, P. alba which difficult to root, the best planting dates was 15" to 22" Feb.. but the effect of root promoters differ during the two planting season. The studied three populus species differ in response to cold storage and ' investigated treatments. Cold storage decreased rooted cutting of Populus nigru and P. ewramericana, while all cuttings of P. alba failed to emerged. P. nigra IBA } at the lowest concentration(250ppm) was effective in improving rooted cutting. 2I days storage period gave the best result. While P. euramericana taken the second order that. 250 to 1000 ppm IBA improved rooting% and 14 days storage period gave the best results . Nitrogen % decreased due the treatments as compared to control for P. nigra and P. euramericana, while. P. alba all treatments increased it as compared with control. As for endogenous hormone the lowest values of IAA were found in P. nigra followed by P. alba and the maximum values was found in P. euramericana. On the other hand ABA was in the maximum values in P. alba followed by P. nigra and then P euramericana. As for total soluble sugars of three Popuius species indicated that, P. nigra stem cutting maintained the highest values of total soluble sugar, followed by P. euramericana and the lowest one was in P. alba. Anatomical structure: P. nigra: root primordia from different regions (pranchymatus cells of callus as well as secondary phloem, cambium zone and pranchymatus area of the outer part of the pith). P. alba: root primordia from cambium zone and pranchymatus area of the outer part of the pith. P. euramericana.: root primordia from the outer part of the pith only.