Development of female hametophytis and embryogenesis of introduced species Picea A. Dietr. in the Taiga Zone (Karelia)

The aim of the research was to establish features in macrosporogenesis, macrogametogenesis, and embryogenesis in Picea species (native species P. abies and introduced species P. canadensis and P. pungens) in the Botanical Garden of Petrozavodsk State University (middle taiga subzone). To study the development of the generative sphere, shoots with generative buds and strobiles from the southwestern side of the crown were cut from 10 trees and fixed in a mixture of alcohol and glycerin. The development of the female gametophyte and the embryo was studied with constant preparations. Preparations for anatomical examination of the kidneys were prepared according to standard methods. In this case, double fixation in glutaraldehyde and osmium was used, wiring through alcohol and acetone, and encapsulation in epoxy resin. Sections with a thickness of about 1 μm were prepared on an ultramicrotome and stained in a 1% aqueous solution of methylene blue. Studies have established that in mid-May, the female gametophyte is still at a free stage, and by the beginning of June it already has a cellular structure. Embryogenesis begins in late July and ends in the second decade of August. In introduced species, various deviations are observed in the development of the female generative sphere and during embryogenesis. The main ones are the degeneration of the female gametophyte at the free-nuclear stage and the destruction of archegonia at the stage of proembryogenesis. For this reason, from 37 to 51% of the seeds of introducers are devoid of the embryo. The largest percentage of empty seeds and the most recent stages of the passage of the main stages of morphogenesis are observed in P. pungens. This indicates the least degree of adaptability of the generative sphere of this species of introducer to new conditions.

The morphogenesis of vegetative buds of Picea species (Pinaceae), introduced in the taiga zone (Karelia)

The observations were carried out in the Botanical garden of the Petrozavodsk state University, located in the taiga zone. Objects of research served 1 native and 5 introduced species: Picea abies (L.) Karst., P. obovata Ledeb., P. mariana Britt., P. glauca (Mill.) Вritt., P. pungens Engelm., P. omorica (Pane) Purk. The study of morphogenesis in vegetative buds was carried out axial shoots from the middle part of the crown since the beginning of the bud swelling until the cessation of laying primordial needles (May to September). The growing shoots are cut off after 2-3 days and were fixed in a mixture of alcohol and glycerin. For the start date of a stage, took the time when it was noted in not less than 30% of the buds. It is established that intrarenal development of vegetative organs from the native species P. abies was studied and introduced species of the genus Picea characterized by similar phases: rest, laying cover scales and laying primordial needles. Morphogenesis of vegetative buds of P. abies on the timing ahead of the development of the bud in the introduced species, which indicates a much greater insistence of the latter to temperature. The duration of the morphogenesis of the buds in all studied types varies slightly (days 131-137). However, the morphogenesis of vegetative buds of native species for 1-4 weeks ahead in terms of development of the buds in introduced species with a similarity of morphogenesis of the bud (P. abies and P. glauca), the value of the annual increment of the shoots is almost the same.

Provenance Trials of the Mexican Spruces in Nursery Conditions: Three Species Endangered by Climatic Variation

The three Mexican spruces’ distributions are fragmented, which could lead to phenological, morphological and genetic differentiation, partially caused by local adaptation. In this study, we examined the effect that climatic variables had on the survival and growth of 5641 Picea seedlings, coming from eight seed provenances of three species and produced in identical nursery conditions. The respective responses of each species and provenance can be considered as a proxy of the genetic differentiation and adaptation of each population. A cluster analysis revealed: (i) significant differences in genetic quantitative traits among the three Picea species and (ii) significant correlations between genetic quantitative traits and climatic factors.

Interactive effects of water and CO2 on light response efficiency and gas exchange traits in pine (Pinus) and spruce (Picea) species

Photosynthetic light response curves were parameterized for eight species in two genera, Pinus and Picea, grown in a 2 × 2 factorial of atmospheric CO2 and soil moisture treatments. Four of the pines and three of the spruces are native to eastern North America, and the fourth spruce, Norway spruce (Picea abies (L.) Karst.), is native to Europe. There was a significant genus × CO2 interaction in apparent quantum efficiency (AQE): spruce AQE was greater under ambient CO2 (CO2) than elevated CO2 (eCO2), but pine AQE were equal. Under drought treatment (DR), AQE declined for both genera. Assimilation at light saturation (Alsat) was greater for spruces than pines, and for both genera, Alsat decreased under eCO2 and DR. Water-use efficiency was greater for pines than spruces and greater for pines and unchanged for spruces under DR. Examining AQE and Alsat change (%) from aCO2 to eCO2, there was a significant positive relationship to biomass growth stimulation (%) across species. These relationships support the theory of sink (biomass growth) regulation of assimilation traits and also the importance of needle nitrogen. Our results in response to eCO2 and DR suggest a shift toward increased use of pines in forest management for eastern North America.

Different Roles of Auxins in Somatic Embryogenesis Efficiency in Two Picea Species

The effects of auxins 2,4-D (2,4-dichlorophenoxyacetic acid), NAA (1-naphthaleneacetic acid) or picloram (4-amino-3,5,6-trichloropicolinic acid; 9 µM) and cytokinin BA (benzyloadenine; 4.5 µM) applied in the early stages of somatic embryogenesis (SE) on specific stages of SE in Picea abies and P. omorika were investigated. The highest SE initiation frequency was obtained after 2,4-D application in P. omorika (22.00%) and picloram application in P. abies (10.48%). NAA treatment significantly promoted embryogenic tissue (ET) proliferation in P. abies, while 2,4-D treatment reduced it. This reduction was related to the oxidative stress level, which was lower with the presence of NAA in the proliferation medium and higher with the presence of 2,4-D. The reduced oxidative stress level after NAA treatment suggests that hydrogen peroxide (H2O2) acts as a signalling molecule and promotes ET proliferation. NAA and picloram in the proliferation medium decreased the further production and maturation of P. omorika somatic embryos compared with that under 2,4-D. The quality of the germinated P. abies embryos and their development into plantlets depended on the auxin type and were the highest in NAA-originated embryos. These results show that different auxin types can generate different physiological responses in plant materials during SE in both spruce species.