End Of Shoot Growth Research Articles

Developmental Characteristics of <i>Sorbus</i> (Rosaceae) Species under Introduction in the Republic of Karelia

Abstract—For twelve years, 14 species of the genus Sorbus L. are growing of in the Botanical Garden of Petrozavodsk State University (South Karelia). They are characterized by a variety of ornamental features – the leaf shape and dissection, flowers, autumn coloring of leaves and fruits. The studied species have different geographical origin: Sorbus americana Marshall and S. decora (Sarg.) C.K. Schneid. are native to North America, S. aria (L.) Grantz, S. mougeotii Soy.-Will. et Godr., S. sudetica (Tausch) Dluff, Nees et Schauer, S. intermedia (Ehrh.) Pers., S. bristoliensis Wilmott, S. × thuringiaca (Ilse ex Nyman) Schonach. – to Europe, S. eburnea McAll., S. koehneana C.K. Schneid., S. amurensis Koehne., S. cashmiriana Hedl., S. sambucifolia (Cham. et Schltdl.) M. Roem – to East Asia, and S. caucasica Zinserl. – to Central Asia. The studied plants have been grown from seeds received in 2010–2015 from the botanical gardens of Russia and abroad. 14 species flowered and fruited for the first time in 2021–2022. Annual shoots of all studied species fully mature by the end of the season. Botanical gardens located at different latitudes provide with data on the cultivated Sorbus species, so it is possible to compare the duration of ontogenetic stages and the dates of the main phenological phases, and to draw preliminary conclusions on the influence of climatic factors on the ontogenetic and seasonal development of plants. The dates of the beginning of the spring vegetation from the middle taiga to Ufa and Stavropol vary by three weeks, and the end of shoot growth – by two months. Along latitudinal gradient from Stavropol to Apatity, the first flowering date varies from the middle of May to the end of July. In the northern regions, the growing season of most of the studied species is shorter than in the southern. A species-specific sequence of seasonal development was revealed: early onset of phenophases in S. sambucifolia, and the latest in S. caucasica, S. bristoliensis, S. eburnea, S. × thuringiaca. According to the first results of a comprehensive assessment of adaptation and viability, all studied Sorbus species are promising as urban greening plants and suitable for further cultivation in southern Karelia.

Использование цифровой фенотеки травянистых растений в декоративном растениеводстве

Abstract. This study shows the improvement of classical methods of studying the growth and development of ornamental plants through the use of modern digital technologies. The purpose of the work is to show students in the direction of 35.03.10 “Landscape architecture” (Decorative plant growing profile) the biological features and decorative qualities of introduced plants in the conditions of the continental climate of the forest-steppe of Western Siberia and to create a digital phenological library. Methods. The construction of the phenospectrum was based on the works of T. I. Fomina and I. N. Beideman. For the design of complete phenospectrum of beautifully flowering plants, it was noted: regrowth, vegetation, budding, flowering, fruit tying, fruit ripening, the end of vegetation. In the abbreviated versions for the digital phenological library, only the periods of vegetation and decorative were noted, the flowering phase was filled with a color corresponding to the color of the variety or species. Calculations for plotting hydrothermal conditions were carried out by standard methods using statistical packages of the Microsoft Excel 2003 program. Results. Examples of single-band phenospectrum characterizing various phenorhythmotypes are given. The advantage of two-band phenospectrum compiled according to the Method of phenological observations for botanical gardens is shown when characterizing plants that create a flowering and decorative-deciduous effect. According to this Method, the phenology of vegetative aboveground shoots includes the phases: B1 – the beginning of spring regrowth; B2 – the unfolding of leaves, B3 – the end of shoot growth, L1 – the beginning of leaf death, L2 – complete leaf death. Additional phenophases are proposed for a more complete description of the spring and summer decorative-deciduous effect. Additional phenophases are proposed for a more complete description of the spring and summer decorative-deciduous effect. For example, Vant or Vlim is a period when young leaves have a bright anthocyanin or lemon color. Additionally, the period of regrowth of summer leaf generation is shown. In the course of training, on the basis of the compiled templates, the method of combining phenospectrum with diagrams of hydrothermal conditions of growing seasons, including abnormally arid and abnormally humid, is also mastered. Scientific novelty. The possibilities of a digital phenological library are shown, which allow to quickly and reliably simulate the flowering and decorative-deciduous aspects of flower expositions and landscape groups based on complete and abbreviated phenomenon spectra. The materials of the digital phenological library complement the visualization of landscaping projects.

Peculiarities of the phenological development of <i>Malus</i> P. Mill species in the conditions of the steppe zone of the southern urals

The article presents the results of phenological observations of five-year-old trees of introduced species and forms of apple trees. The research was conducted in the Orenburg branch of the Federal Horticulture Research Center for Breeding, Argotechnology and Nursery in 2019-2021. Phenological studies were carried out according to the methodology of G. N. Zaitsev, statistical data processing was carried out using the methods of G. N. Zaitsev and B. A. Dospekhov. Data on the passage of 10 phenological phases were used (bud opening, beginning of flowering, end of flowering, end of shoot growth, lignification of shoots, beginning of fruit ripening, end of fruit ripening, autumn leaf coloring, beginning of leaf fall, end of leaf fall). In variable weather and climatic conditions during the growing season, it was found that the timing of the onset of the main phenological phases directly depends on the amount of accumulated positive temperatures, in particular, for the beginning of the growing season, this parameter is 245.2-304.7°C; for the beginning of the flowering phase — 630-609.4°C; the end of shoot growth was accompanied by the accumulation of positive temperatures from 2 152.8 to 2 398°C; at the end of fruit ripening, the sum of positive temperatures was 2 736.3-3 386°C; the beginning of leaf fall corresponds to the sum of positive temperatures from 2 873.9 to 3 200.8°C. In the conditions of the study, the duration of the growing season is 169-176 days, which is a short growing season. Weather and climatic conditions had a significant impact on the processes of active growth and flowering, the genotype of the studied species and forms caused the processes of fruit ripening, lignification of shoots, leaf fall. The duration of the shoot growth period is in direct correlation (r = 0.74-0.81) with the hydrothermal coefficient. The main decorative periods, including flowering, fruit ripening, and the period of autumn coloring, depend to varying degrees on both genotypic characteristics and meteorological conditions in the growing area.

Peculiarities of the phenological phases of the development of pear varieties in the conditions of the steppe zone of the Southern Urals

The article presents the results of long-term studies of the peculiarities of the phenological phases of the development of promising pear varieties of domestic breeding in the conditions of the steppe zone of the Southern Urals (Orenburg region). The research was carried out in 2018-2021 at the experimental site of the 2002 laying of the Orenburg branch of the Federal Research Center of Horticulture. The objects of research were varieties of pears of domestic breeding Krasnobokaya (st), Skazochnaya, Pingvin, Permyachka, Sverdlovchanka, Isetskaya sochnaya, Lel, Chizhovskaya, Lada, Vidnaya, Povislaya (st), Gvidon, Uralochka, Samarskaya krasavitsa, Pamyat of Parshin. The calculation of phenological atypicity to identify the correspondence of the phases of development of pear varieties to the conditions of the region was carried out according to the method of Zaitsev G. N. Statistical processing of the obtained data was carried out in accordance with the methodological recommendations of Zaitsev G. N. and Dospekhov B. A. using the Microsoft Office Excel 10 analysis package. It was established that the studied varieties are characterized by a short growing season — 160-170 days; the required amount of active heat is on average 3 158.9 °C. For pear varieties, the timing of the onset of phenological phases is determined by the accumulated sum of positive temperatures: the beginning of vegetation — 200-304.7 °C; the beginning of flowering – 354-476.6 °C; removable fruit maturity — 2 504-3 603 °C; the end of leaf fall — 3 1793-666 °C. It was found that the timing of the onset of the phenological phases of the beginning of vegetation, the beginning and end of flowering, the end of shoot growth, as well as the duration of flowering periods, shoot growth and vegetation depend more on the conditions of the year than on the genotype. The removable maturity of fruits, the duration of the interphase period, the formation and growth of fruits are determined by characteristics of the variety. The assessment of phenological atypicity revealed that all the studied varieties are in the optimum for the realization of their phenological phases of development.

Структура та морфогенез пагонів видів роду Viburnum L. у Правобережному Лісостепу України

The research was conducted on the structure and characteristics of the growth of shoots of the genus Viburnum L. There are significant differences in the structure and dynamics of growth within the genus, so the determination of the structural features of the shoots of species of the genus Viburnum is relevant. The research of the dynamics of shoot growth was carried out according to the method of A.A. Molchanov and V.V. Smirnov (1967). The species studied by us belong to three sections of the genus Viburnum; the peculiarities of buds structure generally determine the structure of the shoots in the species of each section. It was found that the type of each of the three sections of the genus is characterized by a special structure of the shoots. It has been studied the rhythm of growth and development of native and introduced species of the genus Viburnum L. The terms of shoots growth of the species of the genus were analyzed, and the length of the annual growth of shoots was determined. Phenological date of the beginning and end of shoot growth was established. It was revealed that the onset of individual phenophases quite clearly correlates with the sum of effective temperatures above 5 ° C. The species of the genus Viburnum are characterized by the following types of shoots: tillering, stem, generative. Intensive growth of shoots of all studied species occurs in May - mid-June. In the species of the section Lantana, there are 2 peaks of shoot growth - May and mid-July. According to the duration of growth of shoots, viburnum can be divided into two groups: 1) with a short period of growth (65 - 75 days): V.opulus L., V.sargentii Koehne, V.prunifolium L., V.rufidulum Raf., V.lentago L; 2) with a long period of growth (100 or more days): V.lantana L., V.carlesii Hemsl., V.veitchii C.H. Wright, V.rhytidophyllum Hemsl., V.buddleifolium C.H. Wright, V.burejaeticum Rgl. et Herd. The data obtained demonstrated that the greatest annual growth of all Viburnum species was recorded at the age of 4-7 years. A decrease in the annual growth of axial shoots states the need for works on preliminary rejuvenation of the bush.

Kiwifruit reserves: balancing vine growth and fruit productivity

Storage of large amounts of carbohydrate in the fruit, roots and wood during summer and autumn is vital to produce both high-quality kiwifruit and also to support vine development in the following season. Our study showed that new shoot growth of 'Hayward' vines occurs during the first 100 days after budbreak (DAB) in spring. During this period, vine reserves became depleted, with total carbohydrate concentrations in both roots and wood decreasing by 3-fold and root death occurring in late spring. Although shoots became autotrophic by 30-40 DAB, the concentrations of reserves continued to decline until the end of shoot growth, indicating that insufficient carbohydrate was available from photosynthesis to support the growth and metabolism of the rest of the vine before the end of shoot growth. Once the canopy was established and fruit set had occurred, photosynthate supply was shared between storage in roots and wood, current season's cane and root growth, as well as in fruit development over the remainder of the season. If the supply of carbohydrate was altered or the balance changed during this period, fruit quality, as well as flower production and shoot growth in the following season, was affected. Hence, it is essential to balance vine growth, fruit development and reserve storage to achieve consistent yields of high-quality kiwifruit.

Macronutrient accumulation dynamics in apple fruits

ABSTRACTIn this study, we assessed the macronutrient levels of apple fruits cv. “Golden Smoothee” by monitoring their fruit absorption rates (mg fruit−1 day−1) and accumulation patterns (mg fruit−1) throughout fruit development. Nutrient accumulation was a continuous process throughout the growing season, with patterns of absorption rates varying according to the nutrients concerned. Calcium was chiefly absorbed by the fruit during the first developmental stage, while the greatest absorption rates of other macronutrients occurred later in fruit development (from the end of shoot growth until harvest). From these patterns, it would be desirable to reduce the supply natural calcium (Ca) antagonists, such as potassium (K), ammonium (NH4+), and magnesium (Mg), during the first part of fruit development in order to achieve a good Ca balance with other nutrients and, consequently, an optimum fruit quality. Knowing these nutrient absorption and accumulation patterns is essential for planning optimum nutrient supply and improving their influence on fruit quality.

Autumnal N storage determines the spring growth, N uptake and N internal cycling of young peach trees

Although N storage determines early spring growth in trees, the usefulness of autumn N supply remains unclear as N uptake decreases in autumn, but could be restored earlier in spring to compensate for low N cycling. We intended here to evaluate the effects of autumn N supply on N uptake, storage and cycling, and spring growth. Four levels of N fertilisation were applied to 1-year-old peach trees, between the end of shoot growth and leaf fall. In spring, N supply was 15N labelled. Organ dry weights and concentrations of 14N, 15N, starch and soluble sugars were evaluated after the first growth flush. Bud development had previously been described in the same trees by Jordan et al. (Trees-Struct Func 23:235–245, 2009). Fertilisation promoted autumn N uptake, spring N uptake and growth up to a threshold level, since no differences were evidenced between the three highest N treatments. The variability in tree 14N contents was related to the number of phytomers per tree in autumn, i.e. to tree size. In spring, the depletion of the perennial structures was independent of treatment, indicating a complete mobilisation of the N stores. Spring growth was related to the amounts of cycling N, and spring N uptake was in turn proportioned to shoot and fruit growth. The lower N uptake of the N limited trees was not due to a C shortage since these trees displayed the highest starch concentrations. We conclude that a moderate autumn fertilisation improved spring growth and fruit production (Jordan et al. in Trees-Struct Func 23:235–245, 2009) and that a deficit of N storage could not be compensated for by an increase in spring N uptake.

Sugar transport together with environmental conditions controls time lags between xylem and stem diameter changes

ABSTRACTIn the present study the seasonal patterns of time lags between diurnal xylem and whole stem diameter variations at the top and at the base of two Scots pine trees (Pinus sylvestris L.) were compared. The diameter variations were measured during the summers of 2001 and 2002. Time lags were determined using the cross‐correlation method. The lags were found to vary in time according to the different stages of growth. At the top the xylem lagged behind the whole stem between the beginning of stem growth and the end of shoot growth in both years. In 2001 the time lags at the base showed a similar behaviour during stem growth. That kind of seasonal pattern of the time lags would result from the changes in the sink strength due to changing growth rate at different parts of the tree and the differences in the annual rhythm of growth and water availability in the soil (based on precipitation measurements) between the years 2001 and 2002 were reflected in the patterns. The time lags of shrinking and swelling periods during high and low photosynthetic activity (measured using a shoot chamber) were also compared. It was found, for example, that in 2001 in the middle of the growing season at the top of the tree the whole stem lagged on average 15 min more behind the xylem on the days of high photosynthetic activity than on the days of low or moderate. These results show for the first time that the transportation of carbohydrates and variable sink activity could be detected during the growing season in field conditions using stem and xylem diameter variation measurements. Furthermore, these results provide evidence of the pressure gradient‐driven flow also in the phloem of gymnosperms.

WHITE SPRUCE AND THE SPRUCE BUDWORM: DEFINING THE PHENOLOGICAL WINDOW OF SUSCEPTIBILITY

AbstractSynchrony of insect and host tree phenologies has often been suggested as an important factor influencing the susceptibility of white spruce, Picea glauca (Moench) Voss, and other hosts to the spruce budworm, Choristoneura fumiferana (Clemens) (Lepidoptera: Tortricidae). We evaluated this hypothesis by caging several cohorts of spruce budworm larvae on three white spruce populations at different phenological stages of the host trees, and then comparing budworm performance with host phenology and variation of 13 foliar traits. The beginning of the phenological window of susceptibility in white spruce occurs several weeks prior to budbreak, and the end of the window is sharply defined by the end of shoot growth. Performance was high for the earliest budworm cohorts that we tested. These larvae began feeding 3–4 weeks prior to budbreak and completed their larval development prior to the end of shoot elongation. Optimal synchrony occurred when emergence preceded budbreak by about 2 weeks. Larval survival was greater than 60% for individuals starting development 1–3 weeks prior to budbreak, but decreased to less than 10% for those starting development 2 or more weeks after budbreak and thus completing development after shoot elongation ceased. High performance by the budworm was most strongly correlated with high levels of foliar nitrogen, phosphorous, potassium, copper, sugars, and water and low levels of foliar calcium, phenolics, and toughness. These results suggest that advancing the usual phenological window of white spruce (i.e. advancing budbreak prior to larval emergence) or retarding budworm phenology can have a large negative effect on the spruce budworm’s population dynamics.

カキ'西村早生'の根端細胞分裂と地温との関係

The relation between cell division in the root tips and soil temperature was investigated by comparing Japanese persimmon trees cultured in a plastic house with those grown and outdoors. The air temperature in a plastic house was kept at or over 19 °C from 19 March to 2 June. At every sampling date the 40 root tips from five to ten 23-year-old trees were collected at a distance of 1 m around the trunk and from 10 to 40 cm depth. The tips were dipped in 0.002 M 8-hydroxyquinolin (5°C) for three hours and then fixed in acetic acid-alcohol for microscopy.1. The root tips from trees growing in a plastic house or outdoors exhibited cell division on 22 March. The mitotic index of the roots cultivated in a plastic house increased from 22 March to 2 June when it reached maximum; the high level was sustained until 18 July. It decreased gradually after August; no cell division figure was observed in root tips sampled in 2 October. The mitotic index of roots cultivated outdoors increased gradually until 2 August and then decreased; no mitotic figure was observed in samples collected on 17 September.2. A significant positive correlation existed between the mitotic index of the roots and soil temperatures between March and July. Extrapolating from the relationship, the temperature which induces cell division was 11.7°C.3. The cell division-temperature relationship obtained from August to October indicated that the soil temperature, when the mitotic index decreased, was 21°C.4. Whether the root tips were sampled from trees cultivated indoors or outdoors, they could be white or black. About 40 percent of the root tips sampled between 2 May and August from indoor trees was white; the same frequency of white roots on outdoor trees was observed between 2 June and August. No white root tips were observed after September.5. The mean mitotic index of black root tips was about 0.1%, whereas that of white one was about 0.4%.6. The proportion of white root tips increased as the soil temperature exceeded 19°C.7. The appearance of white root tips had relation with the end of shoot growth or anthesis.

温度条件の相違がウメの冬芽の発達と新梢生長に及ぼす影響

Three experiments on the effects of temperature on the development of winter buds of Japanese apricots (Prunus mume Sieb. et Zucc.) and subsequent shoot growth were conducted in growth chambers and under field conditions.1. From mid-October to mid-February, one-year-old potted seedlings and excised shoots were transferred monthly from field to the growth chamber kept at 15 °C or 25 °C to determine the end of bud dormancy. Bud dormancy of seedlings and that of excised shoots were broken by mid-December.2. The development of leaf and flower buds of 'Nanko' cuttings were compared in growth chambers kept at 0°, 5°, 10°, 15°, 20°, and 25 °C from early January to anthesis. Flowering occurred earlier than did sprouting of leaf buds in cuttings kept at 15 °C or above. No difference was observed between dates of anthesis and sprouting of leaf buds of shoots kept at 10 °C or 5 °C. At 0 °C, flower buds did not develop fully; leaf buds sprouted but the leaves did not expand.3. One-year-old 'Nanko' trees grafted on seedling mume rootstocks were moved on 1 March to growth chambers kept at 10°-15°, 15°, 20°, and 25 °C and held until the end of shoot growth. After sprouting of leaf buds, trees were thinned to 10 shoots per tree. The most vigorous shoot growth was observed in the 10° - 15 °C treatment, in which trees were kept at 10 °C for two months and then transferred to 15 °C. At 20° and 25 °C, shoots ceased their growth earlier than did those in lower temperature regimens.

Citrus Thrips (Thysanoptera: Thripidae) Phenology and Sampling in the San Joaquin Valley

Citrus thrips, Scirtothrips citri (Moulton), was monitored over a 3-year period in San Joaquin Valley, Calif., navel orange groves to compare population trends observed using alternative sampling methodologies and to determine thermal accumulations required for development. Citrus foliage monitoring did not indicate a direct relationship between timing of the end of shoot growth, petal fall, and the level of citrus thrips fruit scarring. Over the first three spring generations, citrus thrips were found in greatest numbers in the northeast quadrant, although first-generation larvae in the south developed more rapidly than larvae in the north. Comparisons among sampling techniques (D-Vac, pupation papers, ground traps, yellow cards, and fruit counts) and their ability to predict scarring were inconclusive. The period between the first and second citrus thrips generations measured from the peak of a particular life stage to the next peak was 156 degree-days above a lower threshold of 14.59°C. The period between the second and third generations was not consistently related to heat units based on this lower threshold.

Phenology and Water Relations of Three Plant Life Forms in a Dry Tree‐Line Meadow

The relationship between physiological and phenological adaptations to drought was examined in three species of different life form in a tree—line meadow in the Sierra Nevada. Soil moisture in this meadow is predictably high following snow melt, but decreases through the summer because of infrequent precipitation. There were large differences among the life forms in allocation patterns and in vegetative and reproductive phenologies, but there were no comparable differences in their water relations. The annual Polygonum minimum and the hemicryptophyte Penstemon heterodoxus respond to decreasing soil moisture by reducing conductance; they consequently maintain a longer activity period. The geophyte Saxifraga aprica has little stomatal control of water loss and becomes dormant as soils dry. Penstemon heterodozus is a long—lived perennial with an intermediate root:shoot ratio (1.9), evergreen leaves, and high allocation to vegetative structures. Leaf growth occurs during the first part of the season, while the soil is moist. Flowering beings at the end of shoot growth, and fruits dehisce 3 mo after snow melt. During a dry summer, plants were observed to lose many leaves; 25% of the plants died, and none of the remaining plants flowered the next year. Although Penstemon decreases conductances under a limited range of leaf water potential, it is still not well adapted to long dry periods. Polygonum minimum is a very small annual with a low root:shoot ratio (0.15) and an indeterminate growth pattern. After a period of solely vegetative growth, leaves and floral structures are produced continually until °soil reaches —5 MPa. Seeds dehisce °2 mo after snow melt. Total seed production is a function of the length of the growth period. Regulation of water balance by stomatal control assures adequate time for fruit production. Other annuals in the community had a very similar phenological pattern. Saxifraga aprica has a high root:shoot ratio (5.0) and a small basal rosette of leaves. Leaf growth occurs for only 2 wk and is followed immediately by flowering. Only 5—10% of the plants flower each year. Fruits mature 5 wk after snow melt, and plants become dormant at —0.5 Mpa or within 6 wk of snow melt. This species and the other ephemeral geophytes complete their growth during the period of predictable high soil moisture, and therefore require little ability to regulate water balance. This study provides evidence that high diversity in life forms is maintained in environments with high yearly variability in the lengths of the drought and snow—free periods. No single set of phenological and physiological characteristics is optimally adapted to the variability in the subalpine environment that was studied, and therefore several adaptive strategies co—occur.