The Response of Vegetable Sweet Potato (Ipomoea batatas Lam) Nodes to Different Concentrations of Encapsulation Agent and MS Salts

As an emerging technology, shoot encapsulation has been employed in germplasm conservation, distribution, and micropropagation of elite plant species. However, the production of synthetic seeds of sweet potato via non-zygotic embryogenesis requires a large number of embryos per cultured callus suspension and is labour-intensive. Here, we reported a simple method of encapsulating in vitro derived vegetable sweet potato nodal segments with sodium alginate, calcium chloride (CaCl2), and Murashige and Skoog (MS) salts. The nodes encapsulated with 4% sodium alginate (w/v) and 100 mM CaCl2 were the most suitable for propagation. They had uniform spherical beads and took the least number of days to shoot and root emergence. These plantlets produced more leaves, roots, and long shoots. Further evaluation of the MS salts concentration revealed that the plantlets encapsulated and grown with ½ MS salts had the least days to shoot and root emergence. They also had a longer shoot, the highest conversion rate (99%), and the least leaf abscission (17%). Thus, the sweet potato nodal segments encapsulated with 4% sodium alginate, 100 mM CaCl2, and ½ MS salts could be used as excellent material for micropropagation, germplasm conservation, and exchange of sweet potato planting materials.

TO THE QUESTION OF MORPHOLOGY OF MYRICA GALE L. GENERATIVE PLANTS

The distribution of Myrica gale on the coast of the Gulf of Finland is confined to regularly flooded coastal habitats, characterized by milder environmental conditions compared to the uplands and under the residual influence of the Gulf Stream. In Russia, M. gale is located on the northeastern border of the range. The study of the features of the species that contribute to the dispersal in the northern direction, and the properties of the environment that prevent such dispersal, is always of great interest. Growth in colder conditions in comparison with other members of the family, mainly inhabitants of the tropical and subtropical areas, affected the formation of such adaptations as deciduousness, changes in the structure of flowers and bark, as well as the presence of a large number of protective leaf organs. Their quantitative and qualitative analysis made it possible to establish the presence of 4 lignified parchment-like scales that do not fall completely and 6 membranous with partially lignified tops scales that stretch out while unfolding. An attempt was made for the first time to analyze the spatial structure of the shoots of the species. A sympodial growth of shoots and the phenomenon of acrotonia, as well as a spiral formation of lateral shoots, were established. In the structure of the mature generative branch of M. gale there were identified 3 types of shoots: long growth, medium and short, and also their leaf series were analyzed. Leaf series of short and medium shoots are characterized by significant asymmetry compared to leaf series of long shoots and are incomplete. The curves were constructed on the basis of such characteristics of leaf organs as their total number, length along the central vein, including the petioles (if they are presented), and internode lengths. A large number of rudiments of leaf organs determines the gradual formation of the buds, and the imperfection of the structure of the scales reflects the weak protective ability of these organs. Both features indicate the deep ancientness of the species and the difficulty in adapting to cold environmental conditions. Mature generative branches of M. gale are similar in habit to small trees, which is of particular interest in the context of modeling possible directions of adaptation during the spread of species of subtropical origin to more northern regions.

Recovery of heather (Calluna vulgaris) flowering in northern Finland

Heather is a slow-growing evergreen shrub, commonly found in moorlands and heaths of high nature conservation value. Heather-dominated areas are used as livestock pasture, and the flowers of heather are harvested also for the natural product industry. Classical studies have focused on the recovery of shoot biomass of heather, while the recovery of flowering after grazing or harvesting has received less attention. In this study, we examined the recovery of heather flowering in one harvesting experiment and two observational areas in northern Finland. The flowers of heather were collected manually by clipping the flowering shoots or stripping the flowers from the shoots or by machine harvesting. We counted the number of short shoots (SS), nonflowering long shoots (NFLS), and flowering long shoots (FLS) after harvesting. We also measured the length of FLS and counted the flowers they produced. Heathers started to recover by producing new short shoots, while the recovery of flowering was slow, and only in one out of the three areas, flowering recovered totally during our study. Our results suggest that the recovery was dependent on the age of heather or individual site characteristics rather than on the harvesting method. Because flowering is one of the most important stages of successful reproduction, which affects the long-term existence of heather-dominated ecosystems, the results of our study can contribute to new guidelines for management practices in heathlands. However, longer-term experiments on the rate of flowering recovery are needed especially if rotational cutting is favored as a management practice in heathlands in the future.

Early Shoot Development Affects Carbohydrate Supply and Fruit Quality of Red-Fleshed Actinidia chinensis var. chinensis ‘Zes008’

Fruit quality characteristics are highly variable across kiwifruit vines due to complex source-sink interactions. We investigated how variation in fruit quality of Actinidia chinensis (Planch.) var. chinensis ‘Zes008’ was influenced by different shoot types (short, medium or long) and rootstocks types (Actinidia chinensis (Planch.) var. deliciosa (A. Chev.) ‘Bruno’ or Actinidia macrosperma C.F. Liang). Short shoots had smaller leaves (−30 to −50%) and lower photosynthesis rates (−0.70 to −3.34 µmol m−2 s−1) in the first cluster of nine leaves (Zone 1) compared with leaves on medium or long shoots. Later in the season, photosynthesis rates in Zone 1 declined with leaf age, but photosynthesis rates were higher (+0.5 to +6.1 µmol m−2 s−1) in later developing leaves on medium or long shoots. Fruit from short shoots had lower dry matter (−0.3 percent units) and lower outer pericarp flesh red pigment scores than fruit from medium or long shoots. At harvest, fruit from vines on ‘Bruno’ rootstocks were larger (+3.7 g), had higher dry matter (+1.3 percent units), soluble solids concentration (+1.7° Brix) and firmness (+0.4 kgf) than fruit from vines on A. macrosperma rootstocks. Factors that prioritised early development of source leaves had a direct impact on the carbohydrate supply from photosynthesis to support flower and fruit development.

Morphological characteristics of Packham’s Triumph pear cultivar fruiting wood

Pear as a fruit species forms various categories of fruit-bearing branches during its life cycle. Depending on how many years it takes to form a young fruiting wood of pear cultivar from its meristem, there can be an annual, biennial, or perennial organogenesis cycle, which in the first place depends on cultivar’s genotype, the rootstock on which the cultivar is grafted, the applied agricultural techniques in nursery and other conditions. Knowledge of the individual pear cultivars organogenesis cycle is the basis for planning regular and stable yields. In order to determine the structure of a fruiting wood for an individual pear cultivar, it is necessary to make analyses on individual increment categories; what is developing from those increments in the following year. The morphological characteristics of annual increments are analysed (spurs, stems, and long shoots) of Packham’s Triumph pear cultivar, as well as the morphological characteristics of each category’s annual increment bourse-over-bourse, all with statistically significant difference between studied factors and factorial levels. Peckham’s Triumph had higher average length of long shoots in both examining years 2011 (53.63) and 2012 (45.33) and William's cultivar had the shorter ones.

Realization of central bud fruitfulness in ‘Syrah’ vines pruned to different lengths of shoots in the piedmont region of Crimea

Приводятся результаты исследований по сорту винограда Сира за 2017-2018 гг. Показано, что плодоносность центральных почек зимующих глазков до 15-го узла побегов по хорошо дифференцированным зачаткам соцветий была высокой, но по сумме зачатков соцветий она была в два раза выше. В угловых глазках побегов по сумме зачатков соцветий значения коэффициента плодоношения центральных почек высокие (1,14), что обеспечивает определенный резерв плодоношения сорта при полной или частичной гибели зачатков соцветий в узлах, расположенных выше. С увеличением длины обрезки от 3 до 12 глазков значения коэффициента плодоношения побегов возрастают от 0,90 до 1,18 с последующим снижением до 1,10. При обрезке на 3 и 6 глазков значения коэффициента плодоношения побегов соответственно сформировались на 27,8 и 1,9% за счет слабо дифференцированных зачатков соцветий центральных почек. В остальных случаях длины обрезки, на 9, 12, 15 глазков, значения коэффициента плодоношения вегетирующих побегов образовались только за счет хорошо дифференцированных зачатков соцветий центральных почек. Наблюдается постепенное увеличение урожайности винограда от короткой обрезки на 3 глазка, где она составляла 138,7 ц/га, до длинной обрезки, на 9 глазков, что привело к урожайности в 176,0 ц/га. Дальше при увеличении длины обрезки урожайность снижается. При очень высокой урожайности по вариантам опыта формируются длинные побеги при их хорошем вызревании, что позволяет устанавливать оптимальную нагрузку перед новой вегетацией. При обрезке на угловые глазки побегов образуется высокий урожай при хорошем накоплении сахаров. В этом случае также формируются длинные побеги. The results of a study of ‘Syrah’ vines in 2017-2018 are discussed. Fruitfulness of the сentral buds of wintering buds was high up to the 15 node of the shoots based on the well-differentiated inflorescence primordia, and twice as large based on the total inflorescence primordia. The numerical values of the coefficient of fruiting of the central buds were high for the base buds of the shoots (1.14) based on the total inflorescence primordia. This enables a certain fruiting reserve in case of total or partial loss of inflorescence primordia in upper nodes. Increased pruning lengths from 3 to 12 eyes led to higher numerical values of the coefficient of fruiting of the shoots within a range of 0.90 to 1.18, followed by a decrease to 1.10. When the vines were pruned to 3 and 6 eyes, the numerical values of the coefficient of fruiting of the shoots were 27.8 and 1.9%, respectively, due to the poorly differentiated inflorescence primordia of the central buds. With pruning lengths to 9, 12 and 15 eyes, the numerical values of the coefficient of fruiting of the vegetating shoots were affected only by well-differentiated inflorescence primordia. Productivity of study vines increased gradually, from 138.7 c/ha when pruned to short length of three eyes, to 176.0 c/ha with long pruning length of nine eyes, yet productivity went down with further increases in pruning lengths. The variants of the experiment showed a very high productivity of study vines in combination with long and well-matured shoots, which enables optimum load prior to the new vegetation period. Pruning to base buds leads to high yields and good sugar accumulation. In this case, long shoots are also formed.

Branching pattern in the ontogenesis of Nepeta manchuriensis (Lamiaceae) individuals

The features development and branching pattern of N. manchuriensis individuals in the conditions of the Far East were studied. It is established that ontogeny consists the ontogeny of the seed individual and the private ontogeny of the ramet. The seed individual pass through the following stages of development: primary shoot-main axis-primary bush-clump-system of partial shoots; ramet: system of partial shoots. Individuals develop according to the sympodial long shooted model of the shoot formation. Basis structure the whole plant is a consistent development of dicyclic rhizomatous-long shoots. The branching pattern is determined by the functioning the buds the first annual growth of the dicyclic shoot. The mechanism of branching occurs according to dychasial type. The geophilic parts of the shoots form a rhizome.

An improved micropropagation protocol for lentisk (Pistacia lentiscus L.)

This study presents an efficient improvement in the in vitro propagation protocol for one cloned genotype of lentisk (Pistacia lentiscus L.) by assessing the effects of gibberellic acid (GA3) concentrations, different cytokinins and amino acids and their concentrations on shoot proliferation, the effects of shoot length on rooting and the effects of compost type (sterile and non-sterile) on acclimatization. The best growth medium for multiple shoot induction was the MS medium supplemented with a combination of 1 mg l−1 BA, 100 mg l−1 tryptophan and 0.5 mg l-1 GA3, which gave a mean shoot length of 1.64 ± 0.07 cm and a mean bud number of 5.46 ± 0.16. The best results in terms of root length, rooting rate and the number of roots per shoot were obtained with 2 cm long shoots. The rooted plantlets were readily acclimatized in the sterile compost. In conclusion, the micropropagation protocol developed in this study can be used for large-scale propagation of P. lentiscus L. in reforestation programmes.

Influence of Paclobutrazol on Shoot Growth and Flowering in a High-density Pecan Orchard

Paclobutrazol (PBZ) was applied to 6-year-old pecan (Carya illinoinensis) trees as a basal trunk drench (0, 30, 90, and 150 mg·cm−2 trunk cross-sectional area) in Dec. 2012. Terminal shoot growth was retarded for 1 year after a single application of PBZ. The total number of current season shoots showed a significant increase with 30- and 90-mg·cm−2 PBZ treatments. After PBZ application at 30, 60, and 90 mg·cm−2, the percentage of very short shoots (<5 cm) was 32.3%, 36.3%, and 32.3%, respectively, compared with 22.4% on control trees; the percentage of short shoots (5–15 cm) increased to 36.0%, 38.1%, and 43.5%, respectively. The percent of long shoots (>30 cm) was decreased to 7.4%, 5.1%, and 7.6%, respectively, after PBZ application, compared with 18.7% with control. Shoots varying from 5 to 30 cm in length accounted for at least 63.3% of all pistillate inflorescences the following spring.