The effect of acclimation to drought in seedlings of Mediterranean evergreen sclerophyll Laurus nobilis L. (laurel) was studied in semiarid field conditions. The phytohormones abscisic acid (ABA), gibberellic acid (GA 3), zeatin (Z) and indole-3-acetic acid (IAA) contents, plant water potential, photochemical efficiency, and morphological characters were determined. Seedlings were acclimated to...

Spermine (Spm) is thought to play an important role in drought or high-temperature (HT) tolerance. However, it is not clear whether Spm confers similar resistance in the presence of both drought and HT, which often occur simultaneously. In the present study, the trifoliate orange (Poncirus trifoliata (L.) Raf.) seedlings were pretreated with 1 mmol L-1 Spm to evaluate their tolerance to combine...

Successful tree regeneration requires both successful seedling establishment and subsequent survival and growth suf®cient to ensure recruitment. We examined patterns of initial seedling establishment in randomly selected stands of eastern hemlock (Tsuga canadensis) distributed across northern Wisconsin and eastern Upper Michigan. In 1990, we counted all hemlock seedlings (de®ned as 4±29 cm tall...

The effect of a short period of elevated temperature, or heat shock, on protein synthesis was investigated in 2-day-old seedlings of jack pine (Pinus banksiana Lamb.), loblolly pine (P. taeda L.), lodgepole pine (P. contorta Dougl.), black spruce (Picea mariana (Mill.) BSP), and white spruce (P. glauca (Moench) Voss.). In all species, heat shock led to increased [(35)S]methionine incorporation ...

The effects of salicylic acid (SA) on the accumulation of dehydrins in leaves of Tibetan hulless barley seedlings under water stress were investigated. The results indicated that SA decreased the levels of the four dehydrin-like proteins induced by water stress. The concentrations of these dehydrin-like proteins increased under water stress. However, their levels in SA-pretreated seedlings were...

Cytokinin replaces light in several aspects of the photomorphogenesis of dicot seedlings. Arabidopsis thaliana seedlings grown under red light have been shown to become disoriented, losing the negative hypocotyl gravitropism that has been observed in seedlings grown in darkness or white light. We report here that cytokinin at micromolar concentrations restores gravitropism to seedlings grown un...

KRAIGHER H. & HANKE D.E. 1996. Cytokinins in Norway spruce seedlings and forest soil pollution. Phyton (Horn, Ausrtia) 36 (3): (57) (60). Cytokinins can correlate with pollution damage in spruce trees and also with different strains and species of their mycorrhizal symbionts. In our study, Norway spruce seedlings were grown in vitro on sterilized or nonsterile soil substrates from two different...

Water oak is often used in afforestation projects in the Lower Mississippi Alluvial Valley, but its field performance is often poor due to low survival rates and severe top dieback immediately after planting. The poor physiological quality of planting stock may be a contributing factor to this transplanting problem. In this study, cold storage was investigated to increase dormancy status of see...

A bstract. Kinetin in concentrations of 10-e to 10-4 M, stimuated ethylene production in 3 and 4-day old etiolated seedlings of Alaska pea (Pisucm sativum L. var. Ala-ka). Seedlings of other species responded similarly. The response to kinetin depended on the age of the seedlings. Kinetin alone did not influence ethylene production in 6-day old stem sections, but it greatly increased the enhanc...

Paulownia witches' broom (PaWB) caused by phytoplasma might result in devastating damage to the growth and wood production of Paulownia. To study the effect of phytoplasma on DNA sequence and to discover the genes related to PaWB occurrence, DNA polymorphisms and DNA methylation levels and patterns in PaWB seedlings, the ones treated with various concentration of methyl methane sulfonate (MMS) ...