Growth and Development of the Introduced Picea L. (Karst.) Species in the Taiga Zone (Karelia)

The study was conducted in the Botanical Garden of Petrozavodsk State University (South Karelia, the middle taiga subzone) from April to October during 1988–2016. The following representatives of the genus Picea were investigated: four introduced species (Picea glauca (Moench) Voss [syn. P. canadensis Britt.], P. pungens Engelm. f. viridis Regel., P. obovata Ledeb., and P. mariana Britt.) and one native species (P. abies (L.) Karst.). The growth of P. abies shoots starts 1–4 weeks earlier and ends 1–3 weeks later compared to the introduced species. The earliest culmination of shoot growth is observed in P. glauca and P. obovata and the latest in P. abies. The longest shoots are formed by P. abies. The growth dynamics of shoots differs considerably between the introduced species and the native species. The dates of the beginning and the culmination of the shoot growth in the studied species are to a certain extent affected by the temperature of the air. P. abies needles begin to grow 1–2 weeks earlier than the needles of the introduced species. The earliest culmination of needle growth is observed in P. obovata and P. glauca and the latest in P. pungens. P. abies and P. pungens show the largest needle length increment, while in the other species, it is 2–4 times smaller. The longest needles are formed in P. pungens and P. abies. There is a noticeable difference in needle growth dynamics between the introduced species and the native species. The dates on which needles begin to grow are largely determined by the temperature of the air. The temperature of the air and solar radiation produce a substantial effect on the time of occurrence of most phenophases in the studied Picea species. P. pungens and P. glauca were found to be the most promising spruce species for residential landscaping and creation of artificial plant communities in Karelia

Comparing Primary and Secondary Growth of Co-Occurring Deciduous and Evergreen Conifers in an Alpine Habitat

Investigations on primary and secondary growth in co-occurring species will aid in assessment of the physiological adaptation of species and the prediction of forest stand structure dynamics. To explore the correlation and coordination between primary and secondary growth, we monitored the leaf phenology, shoot elongation, and stem growth of co-occurring Larix principis-rupprechtii Mayr. and Picea meyeri Rehd. et Wils. in an alpine habitat, Luya Mountain (North-Central China), during the growing season of 2014. We measured bud development on terminal branches three days per week by direct observations and intra-annual stem xylem formation at weekly intervals by the microcores method. The onset sequence of three organs was the needle, shoot, and stem, without species-specific differences. Needles appeared one month earlier than stem growth in larch, while it was only one week earlier in spruce. The duration of needle growth was the shortest, followed by the shoot and stem. The timing of primary growth (i.e., onset, end, and maximum growth rate) between the two species was asynchronous, but secondary growth was synchronic with the same date of the maximum growth rate occurrence, potentially indicating species competition for resources. Unlike larch, spruce staggered growth peaks among different organs, which may effectively mitigate trees’ internal competition for resources. Soil temperature was positively correlated with both shoot and stem growth in the two species, whereas air temperature and soil water content were positively correlated with needle growth only in larch. Therefore, it can be inferred that the spruce will probably outcompete the larch at cold alpine treeline sites due to its high adaptability to acquiring and allocating resources. These results provide insight into the potential physiological correlation between primary and secondary growth and allow better prediction of future climate change effects on forest ecosystem productivity.

Peculiarities of seasonal growth of Pinus nigra J.F. Arnold under the conditions of introduction in the Right-Bank Forest-Steppe of Ukraine

Generalization of scientific studies and analysis of experimental data on the peculiarities of seasonal growth of vegetative organs of Pinus nigra J.F. Arnold, their compliance with the climatic conditions of the Right-Bank Forest-Steppe of Ukraine are reported. Studies showed that the mechanisms of regulating growth processes are directly affected by the air temperature. P. nigra belongs to the species that begin their vegetation early in spring. The first shoots to start growing are the ones which require a small amount of heat. Studies showed that the needle growth begins on the 30th–35th day after the onset of shoot growth. During the study period it was also noted that the growth intensity of shoots is gradually increasing from the base of the crown to its top.

Distribution of radioactive products of photosynthesis in Scots pine (Pinus sihestris L.) seedlings during the first vegetation season

Dynamics of translocation and distribution of radioactive photosynthetic products in one year old pine (<i>P. silvestris</i> L.) seedlings was investigated at different growth stages. It was found that the utilization of photosynthetic products in particular organs depends greatly on the growth stage. Loses of photosynthetic products as a result of respiration were the smallest at the stage of intensive needle growth and the greatest at the stage of approaching dormancy.

DYNAMICS AND TOPOGRAPHY OF QUASI-2D NEEDLE-LIKE SILVER ELECTROCHEMICAL DEPOSITS UNDER A QUASI-STEADY-STATE REGIME

The electrochemical formation of single silver needles from aqueous silver sulfate was studied under both potentiostatic and galvanostatic conditions utilizing different quasi-2D cells. Under potentiostatic conditions, four (I–IV) stages of growth were distinguished. Stage III involved single needle growth under a quasi-steady-state (q-ss) regime in which, at the millimeter scale, the tip profile remained almost unchanged. Fast growing needles exhibited a truncated quasi-conical tip, and slow growing ones approached prolate hemispheroids. At stage III, the almost constant q-ss silver deposition rate was evaluated from the tip front displacement (dL z /dt) perpendicularly to the tangential plane of the tip. For the cathode to anode potential difference in the range -1.00 ≤ E c-a ≤ -0.22 V , values of (dL z /dt) in the range 0.08–2.0 μm s-1 were obtained. At the needle stem, the q-ss radial silver deposition rate (dL x /dt) was about two orders of magnitude lower than (dL z /dt). The transition from stage III to IV was characterized by tip thickening, i.e. a change in the tip q-conical profile to that of a prolate hemispheroid, and eventual tip splitting. Scanning electron micrographs at the micrometer scale of single silver needle tips from potentiostatic runs showed either a defined crystallography or an irregular topography covered by a large number of tiny crystals. In contrast, stems were always faceted. This difference indicated that surface relaxation processes following silver ion mass transport and discharge played a relevant role in the needle growth mode. At stage III, the growth regime is described utilizing a dual diffusion (D) and migration (M) model consisting of a DM direct contribution that becomes dominant at the needle stem, and a space charge (SC)-assisted DM contribution that operates at the tip apex. This explanation is consistent with the local cathodic current density values, the concentration ratio of silver clusters at the stem and tip apex surface, and the distinct kinetic behavior of needles produced from potentiostatic and galvanostatic runs. The complex link between mass transport phenomena of silver ions from the binary solution side, the silver ion discharge at the interface and the surface relaxation of silver adatoms and clusters at the metal lattice shed new light on the aspects of single silver needle formation.

Interaction Between Bacteria, Nannobacteria, and Mineral Precipitation in Hot Springs of Central Italy

ABSTRACTA complex of inorganic and organic factors controls precipitation of carbonates in hot springs of Lazio, central Italy. A plot of data from this area shows that the main /norganic controls are temperature and Mg/Ca ratio of the spring waters. Virtually all springs with waters hotter than 400C precipitate aragonite, and cooler ones form calcite. Furthermore, even cold-water springs precipitate aragonite if the Mg/Ca ratio exceeds 1:1, except in two cases. To what extent is the precipitation of travertine inorganic vs. biochemical? Surely, conditions in diverse localities can vary between both end-points, but Le Zitelle springs, at the north flank of the caldera of Viterbo, provide a biochemical extreme. Waters are hot (600C), with Mg/Ca of .2, and are highly sulfurous. Carbonate precipitation rates can exceed 2 mm/day. /Vonetched samples of carbonate crusts, only minutes to a few hours old, exhibit aragonite, calcite, and 1- to 5- (im euhedral rhombs of probable dolomite. Aragonite forms spherical "pincushions" of radial needles, each needle tipped with a nannobacterial body of the same diameter as the needles, 0.1 to 0.4 jim. Each nannobacterium precipitated its own needle, and was propelled outward by needle growth. As little or no later "fattening" of the needle occurred, inorganic precipitation must have been insignificant here. fVonetched calcite crystals are composed of 0.05 (xm nannobacterial spheres that were incorporated into each layer of the crystal as it grew. No evidence of bacteria was found on the ?dolomite rhomb surfaces. Ironically, aragonite, calcite, and euhedral ?dolomite rhombs all grew within minutes to an hour of each other in the same solution under the same conditions, savaging all the rules exposed at the beginning they remain a baffling problem unresolved by chemistry, physics, or microbiology.