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.

GERMINATION AND POST-SEMINAL DEVELOPMENT OF Melaleuca alternifolia (MAIDEN & BETCHE) CHEEL

ABSTRACT There is little information regarding the germination pattern, seed characterization, and seedling development of Melaleuca alternifolia. This study aimed to determine the ideal temperature for the germination of M. alternifolia seeds, as well as to characterize the seeds and the post-seminal development of the species. Three lots of M. alternifolia seeds were placed to germinate at 20, 25, 20-30, 20-35, 30, and 35 °C, with daily evaluations to determine germination rate, germination speed index (GSI), speed of germination (SG), and mean time for germination of 50% (t50) and 100% (t100) of seeds. The inner morphology of the seeds was evaluated through X-ray images and seedling morphology by photographs. Alternating temperatures (20-30 and 20-35 °C) led to germination rates higher than the other temperatures. The GSI had the lowest values at the constant temperature of 20 °C and the highest values at the constant 30 °C for all the lots. The SG was lowest at a temperature of 20 °C and the highest at the temperature of 35 °C. At alternating temperatures (20-30 and 20-35 °C), t50 was around 5 days and t100 reached 16 days. In conclusion, the alternating temperatures of 20-30 °C and 20-35 °C are recommended for germination of M. alternifolia, and final evaluation can be performed at 16 days after sowing. The inner structures of seeds could be visualized by X-ray analysis, and full seeds could be distinguished from empty seeds and impurities. Seeds exhibit epigeal germination and seedling development is stabilized after 30 days.

Cone and seeds variability in seed orchards and seed stands of Pinus sylvestris L.

Seeds from seed orchards and seed stands may differ in morphology and quality, both determined during the seed assessment. The study aims at the comparison of phenotypic characters of cones and seeds originating from economic seed stands and seed orchards of Scots pine from western Poland. The study was conducted in 5 seed stands and 5 clonal seed orchards, representing five Scots pine populations. The analyses included the following measurements: length and width of cones, the number of empty and full seeds in the cone and the weight of 1,000 seeds. Moreover, the measurements of the length and width of the seed surface were carried out. The analysed seed stands and orchards were characterized by high variability in terms of the size and weight of cones and the amount of seeds. An ANOVA treatment showed that seed stands and orchards significantly differed in length and width of cones and seeds. Both seeds and cones from the seed orchards were characterized by higher values of analyzed traits than ones from the economic seed stands. Differences in mass of cones and 1000 seed weigh were of low significance (p = 0.022 ÷ 0.037). Significant differences between the length of seeds and seed area among all of the examined populations were demonstrated. The percentage contribution of empty seeds for all of the analysed sites of origin was not statistically significant. Keywords: Scots pine, population, seed orchards, variation, seeds, cones

Germination of Pulsatilla Seeds as Influenced by Seed Morphology, Moist 5 °C and Gibberellin (GA3) Treatment, and Detection of Nickel in Seeds

Seeds of Pulsatilla turczaninovii were categorized to full and empty seeds based on observations under a light microscope and on X-ray images. A germination test for full or empty seeds was evaluated as affected by the duration of gibberellin GA3 and the moist 5 °C cold stratification (CS) treatment. The morphological and elemental components of P. turczaninovii and P. cernua var. koreana seeds were analyzed using low-temperature scanning electron microscopy (LT-SEM) and energy dispersive X-ray diffraction analysis. The results showed that 64% of full and semifull P. turczaninovii seeds 10 weeks after harvesting germinated in 17 to 19 days; however, the germination rate, including empty and semiempty seeds, was lower (52.6%). Full seeds with damaged or dried vegetative organs (embryo or endosperm) and semifull seeds with severely damaged vegetative organs were observed, and this result could be related to low germination rates. Germination patterns of seeds stored dry at 5 °C for 44 weeks that showed a sigmoid pattern were increased by immersing seeds in a GA3 solution for 8 hours and treating seeds with 16 or 32 days of CS. More seeds germinated between 12 and 17 days (as compared with 17 to 29 days), especially when they were treated with GA3 and received 32 days of CS. Comparison of germination rates of visually full seeds upon harvest (52.6%) with those that had been stored dry for 44 weeks (26.3% to 29.7%) suggested that the viability of seeds may have decreased. Dormancy could be a factor that decreased germination and can be removed by low temperature and GA3 treatment. LT-SEM revealed a valley-like, sunken streak in empty seeds of P. cernua var. koreana. The nickel content in the trichome and seedcoat of full and empty seeds of both taxa ranged from 2.98 to 4.62 (weight %), as determined on X-ray images. Our study suggested that the low germination rate was due to either the presence of dormancy, damage to either embryo or endosperm, a loss in viability, or the presence of nickel in the seeds.

RESISTANCE OF SEVERAL RICE VARIETIES AGAINST THE BACTERIAL PANICLE BLIGHT DISEASE (Burkholderia glumae)

Resistance of Several Rice Varieties against the Bacterial Panicle Blight Disease (Burkholderia glumae) .Burkholderia glumae is included as A2 Quarantine Plant Pest Organism, which is found in some restricted area in Indonesia. B. glumae is a seedborne pathogen that causes panicle blight, seedling rot, grain rotand leaf sheath browning on rice plants. This research was objected to determine the resistance of five rice varieties against bacterial panicle blight pathogen. The experiment was carried out at the screen house of Faculty of Agriculture, Universitas Sumatera Utara, Medan from May to September 2018. This experiment was designed using Factorial Completely Randomized Design (CRD) with 2 factors; Factor 1: B1 (sterile water as negative control), B2 (B. glumae isolate CH BJ), B3 (B. glumae isolate IR 64), B4 (B. glumae isolate IC PRC), B5 (B. glumae isolate DSMZ 9512ᵀ as positive control). Factor 2: V1 (Cisokan variety), V2 (Inpari 4 variety), V3 (Situbagendit variety), V4 (Inpari 32 variety) and V5 (Cidenu variety). The results showed that all five rice varieties were highly susceptible to bacterial panicle blight pathogen. Inpari 32 variety had the highest number of seeds and weight of 100 seeds and had the lowest percentage of empty seeds. IR 64 variety had the lowest number of seeds and the weight of 100 seeds and had the highest percentage of empty seeds.

Environmental and physiological effects on cross-ability and seed production of greenhouse cucumber

Seed production depends on many factors. In this study, two independent experiments were carried out to investigate the effects of pollination time, crossed node spacing, male flower age, number of crossings on each plant and deletion/non-deletion of other fruits in the crossed nodes on the cross-ability and seed production in greenhouse cucumber. In every experiment, three mentioned factors were assayed based on factorial experiment as a randomized complete block design. Crosses were done on 10 plants in every replication of treatments. The results showed that pollination at 8:00‒9:45 AM, led to higher amount of full seed weight in contrast to other times of pollination. Increasing crossed node spacing from 2‒3 to 4‒5 nodes led to an increase in the number of empty seeds, which was ascribed to the reduced seed production. The highest amount of number of seeds per fruit, seed weigh and number of full seeds were obtained when young male flowers were used. Moreover, higher seed production was obtained from five, instead three crossings on each plant, and the non-deletion of fruits on the crossed nodes. Overall, higher percentage of seed production per fruit was obtained when crossing was done with young male flower in early morning and high number of crossing in every plant.

Effect of pre-sowing treatments on seed germination and seedling vigour index of Abies spectabilis (D.Don) spach

An experiment was conducted to study the effect of pre-sowing treatments on germination of Abies spectabilis commonly called as “Talispatra” - an important high level conifer of Western Himalayan region. The seeds of Abies spectabilis collected from Kalabagh near Churdhar area of Shimla district (H.P.) were given different pre-sowing treatments of cold moist stratification in sand for 1 to 4 weeks and control (untreated seeds) to study their effect on germination behaviour and seedling vigour index. Significant differences were observed in germination per cent and seedling vigour index of seeds subjected to different pre-sowing treatments. The maximum germination per cent (42.00%) was recorded in seeds treated with cold moist stratification treatment in sand for 1 week followed by 36.00 per cent germination recorded for control (untreated seeds). The minimum germination per cent (19.50%) was recorded in seeds treated with cold moist stratification treatment in sand for 4 weeks. The findings of the present investigation revealed that Abies spectabilis seeds do not possess any dormancy and the poor germination is primarily due to presence of large number of empty seeds.

Germination of Fully Developed Corylopsis Seeds Influenced by Harvest Date and Cold Stratification

Corylopsis seed germination tests were conducted to assess the influence of harvest date (seed maturity) and cold stratification (CS) at 5 °C. Corylopsis gotoana seeds harvested on 12 July, 2 and 22 Aug., 6 and 20 Sept., and 1 and 10 Oct. 2011 were immersed in water for 20 min to separate fully developed seeds (full seeds) from empty seeds by floatation, and by X-ray scanning to identify full from empty seeds (Expt. 1). Immersing seeds in water did not effectively separate full seeds from empty seeds as evaluated by seed germination tests. Seeds harvested on or around 6 Sept. that sank showed translucent X-ray images with fully developed internal structures composed of embryo, cotyledons, and endosperm, and were considered mature. Without CS, >12% seeds harvested on 20 Sept. germinated, regardless of whether seeds were full or empty. Seeds of C. coreana harvested on 5 and 15 Sept., and 5 and 18 Oct. were stored dry at 20 °C until 27 Dec. and germinated after 0, 3, 6, 9, and 12 weeks of CS (Expt. 2). Longer than 6 weeks of CS was required to accelerate and increase the germination of seeds harvested on or after 5 Sept. Germination percentage of full seeds harvested on Oct. 18 was increased to >72% as the duration of CS treatment increased to 12 weeks. In conclusion, fully developed seeds harvested on or after 6 Sept. were considered mature and 6 weeks of CS accelerated germination and increased the germination percentage. Further, dormancy of Corylopsis seeds appears to be shallow since germination occurred without any CS.

Cone quality and seed efficiency in the clones from mutational witches brooms of Pinus sibirica

Mutational witches' broom is a fragment of the tree crown with abnormal morphogenesis including slow shoot growth, abundant branching and decreased apical dominance which caused by somatic mutation that presumably originates in the apical meristem bud. To study the variability in the cone quality and seed efficiency in witches' broom clones of Pinus sibirica, the cone size and structure were assessed in 21 mutant clones. The mutant clones were significantly differentiated both by the cone traits and seed quality. Their cone size varied from less than 3 to 4 cm. The clones had large number of sterile scales in proximal and distal cone parts, and from 16 to 39 fertile scales per cone. Cones from all mutant clones were inferior to average normal cones of the species. Six clones had large portion of filled seeds, more than 70%, and the other clones had less than 50% of filled seeds. The clones had 10-33% of empty seeds and 1-73% of seeds with collapsed megagametophyte per cone. In general, the seed quality in mutants was quite low, but individual clones had almost normal seed quality, and their seed efficiency was within the species norm.