We examined whether peroxidase activity in cutting bases and leaves and starch content in cutting bases can be used as rooting phase markers in the elepidote rhododendron cv. 'Babites Baltais' (Rhododendron L.). Changes in peroxidase activity in cutting leaves and bases, as well as starch content in cutting bases, were determined in relation to anatomical stages of rhizogenesis in leaf bud cuttings treated with 1% indole-3-butyric acid (IBA+) or without IBA (IBA-). The pattern of change of peroxidase activity was similar in cutting bases and leaves of IBAleaf bud cuttings. Three phases of adventitious root formation were identified: induction, initiation and expression. During the induction phase peroxidase activity decreased, but no anatomical changes were observed in the cuttings. Peroxidase activity increased in the initiation phase when adventitious root initials were formed. Peroxidase activity decreased during the expression phase when adventitious root primordia developed. The starch content of IBA-leaf bud cuttings decreased during the first few days and then gradually rose to maximum, followed by a sharp reduction and another increase at the end of the experiment. The changes of starch content did not coincide with rooting phases as peroxidase activity did, and cannot be used as a rooting phase marker in rhododendrons. Adventitious root formation did not occur in IBA+ leaf bud cuttings, so distinct rooting phases could not be observed. There was a significant correlation between peroxidase activity in cutting bases and leaves of IBA-leaf bud cuttings. Peroxidase activity in leaves of rhododendron leaf bud cuttings are potentially useful as a marker for rooting phases, but that requires further anatomical and physiological study of rooting in leaf bud cuttings.K Ke ey y w wo or rd ds s: : Peroxidase, starch, adventitious root, leaf bud cuttings, rhododendron.

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Rape (Brassica napus L. var. napus) is long ago-known vegetable of Brassicaceae in agriculture. It is important and valuable oil, forage, green-fertiliser and nectar plant. The experience of last years shows that rape is suitable for growing in conditions of Latvia, but investigations about its cultivars and growing technologies are not wide enough.The phosporus-fertilizer adding in the rape plantations is of great importance for increasing of its productivity. With the aim to reduce the expenses the phosphorus treated rape seeds are made use.In our investigations the velocity of seeds germination, germinating viability, germinating vigour, green pigments” quantity in seed-lobes and seeds” corp are studied. The conclusion is drawn that phosphorus treated seeds are of elevated physiological activity and elevated quantity of chlorophyll in seed-lobes, the seed-corp is increased for 3-70%. The velocity of the seeds” germination, germinating ability and germinat ing viability is increased too.The making use of phosphorus treated seeds is of great effectiveness because it gives the possibility to prevent phosphorus-lack in plants and to increase physiological activity and productivity of plants.

Visu savu darba mûþu Aldonis Vçriòð veltîjis puíu kultûru hibridizâcijai un selekcijai, pievçrsdamies galvenokârt gladiolâm, lielziedu îrisiem un peonijâm.Augu bioloìijas pamatus Aldonis Vçriòð apguva Latvijas Valsts universitâtes Bioloìijas fakultâtç un pçc studijâm darba gadus nostrâdâja ar bioloìiju un puíkopîbu saistîtâs darba vietâs -LVU Botâniskajâ dârzâ, Dabas muzejâ, Rîgas Dârzkopîbas un biðkopîbas biedrîbâ, agronomijas un dârzkopîbas þurnâlos.