We present some results of a six-year (2008-2013) study in two localities of Liparis loeselii (L.) Rich. near Lake Engure. The annual cycle of L. loeselii, an early successional species, may indicate its potential survival in its typical wet habitat with fluctuating levels of water. Flowering of L. loeselii usually begins in the first decade of June and lasts for several weeks. If the initiation of development was delayed, leaves and inflorescence started to grow almost simultaneously. Development of the first fruit began during flowering and continued to August. Ripening of fruit and seeds occurred in September-October, and they were dispersed mostly by melt water of snow in spring, which is very important for populations in sites overgrowing with perennial herbs. The previous season capsules of L. loeselii remained till the middle of the next growing season; a part of the seeds remained in capsules and less than 1% of seeds had viable embryos. This may increase the survival potential of the population. The studies of herbarium records of L. loeselii in the area of Lake Engure showed that the annual cycles of L. loeselii have been similar and that the species has not responded drastically to climate change.
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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