Reproductive Buds Research Articles

Heat stress during reproductive development inhibits fertilization in olives

In this study, we investigated the effect of heat exposure during olive inflorescence on reproductive development. We hypothesized that male development processes during this period are particularly sensitive to high temperatures. We characterized the development of flowers and inflorescences under natural conditions in the cultivars 'Arbequina' and 'Koroneiki', and defined eight phenological stages, beginning with the emergence of reproductive buds until anthesis (international standard BBCH scale of the phenological inflorescence development phases 53–60). In addition, we examined the response of olive inflorescence and flowering, to two heat scenarios: prolonged exposure to moderately high temperatures and a two-hour concentrated heat shock treatment. Analysis of our data revealed that both treatments had a detrimental effect on the development and functioning of the tapetum, the innermost layer of the anther, which is essential for the development and functioning of pollen. Additionally, we found that the 'Arbequina' cultivar displayed relative tolerance to heat compared to 'Koroneiki' in terms of pollen germinability after heat stress. In contrast to the response of the above cultivars, the 'Souri' exhibited an exceptionally high sensitivity to heat. An assessment of pollen viability after in vitro heat shock treatment of 54 cultivars revealed that pollen from seven varieties, 'Niedda de Oliana', 'Lechín de Sevilla', 'Tonda Oliana', 'Tamir', 'Sigoise', 'Taggiasca', and 'Carrasquenha', showed exceptional tolerance to heat. These cultivars show a greater degree of suitability for cultivation in warm climates, (or in areas susceptible to extreme hot-spells). This study demonstrated that heat has a negative impact on the male reproductive system in olives, during early flower development and in mature pollen grains, which are relatively resistant to heat. Heat stress impaired pollen tube elongation capacity, and germination rate. Additionally, heat stress affected the ultrastructure of the external wall of the pollen grain, the exine, potentially impairing its ability to adhere to the stigma and fertilize the ovule. The sensitivity of olive reproductive capacity to heat is a genotype-dependent trait, allowing for the identification of heat-resistant cultivars for use as pollen donors and for development of new heat-resistant cultivars.

Physiological and molecular insights into the alternate bearing in mango (Mangifera indica L.) using next-generation sequencing approaches.

India's mango productivity is hindered by many factors but more importantly due to limited understanding of the genomic complexities behind regular bearing habit. This study is the first to quantify carbohydrate fractions, protein content, and macro and micronutrient storage pools, their transportation, and contributions to regular 'Totapuri' and alternate bearer 'Bombay Green' mango varieties during the 'off' year. Deep RNA sequencing was used to assess gene expression dynamics between buds and flowers of these varieties. Differential pathway analysis showed the greatest number of differentially expressed genes in metabolic processes (1377), followed by oxido-reductase (879), hormone (80), oxidative stress (77), starvation (39), alternate bearing (8), flowering (3), meristem (3), and cellular component (2) pathways. In silico analysis showed that among 15 genes, twelve genes up-regulated in Totapuri and three in Bombay Green, confirmed by qRT-PCR. Additionally, 202 SNPs were identified in 32 alternate bearing-related genes. The study confirmed the reproductive bud's strong ability to import sugars, protein, and starch in the regular bearer variety, enhancing flowering and fruiting during off years. The mineral nutrients and biochemical constituent of the bud and leaf tissue in contrasting genotypes, showed the potential role for regular bearing in mango.

In Planta Androgenesis (Paternal Origin) in Saacharum X Erianthus Intergeneric Hybrid

The present investigation was carried in crosses made between Saccharum species hybrid clones i.e. Co 419, Co 7201 and Co 7224 (2n = 108-112) and Erianthus arundinaceus viz. IK 76-91 (2n = 60) and IK 76-99 (2n = 60) for introducing better ratoon ability, vigour, wide ecological adaptability, extensive root system, drought and water logging resistance, high biomass and disease resistance into modern sugarcane cultivars during 2020-23 at VSI-Sugarcane Breeding Centre, Amboli. Parental apomixis (paternal origin) has been recently noticed and it is unique in Saccharum X Erianthus intergeneric cross seedlings. A total of fifty-one seedlings were obtained from above three intergeneric crosses and out of these eighteen seedlings were reported as androgenetic seedlings as the female act as a surrogate mother. At the early stages, seed germination of seedlings was found two types i.e., one type resembling Saccharum and other resembling Erianthus with deep purple coloration. Morphologically androgenetic seedlings were similar to the male parents IK 76-91 and IK 76-99 with tall large tufted grass like clumps, vegetative stem with thick reproductive buds, root zone narrow and only one row of root eyes, the lamina gradually passes into leaf sheath with no auricle and dewlaps. Cytological studies were made in these seedlings and during metaphase the somatic chromosome number was observed to be 2n = 60 rather than expected 2n = 84-90. This paternal origin may be due to the ability of Erianthus male gametes to produce an embryo within the seed tissues of Saccharum species hybrids but without genetic contribution of the seed. Thus, in planta androgenesis is achieved through the combination of embryogenic behavior of male gametes which has entered in the ovule and the ability of ovules to act as a surrogate mother. They could derive either from the fusion of two male gametes or from the early natural diplodization of the haploid embryo. Such homozygous true breeding seedlings of Saccharum X Erianthus with hybrid vigour are extremely important in crop improvement. This system provides an unparalleled opportunity to shorten the breeding cycle and fix agronomic traits in the homozygous state. These androgenetic plants with Saccharum cytoplasm and Erianthus genome are male sterile making them highly useful for further hybridization and sugarcane improvement programme.

The Molecular Biology Analysis for the Growing and Development of Hydrangea macrophylla ‘Endless Summer’ under Different Light and Temperature Conditions

Hydrangea macrophylla, a celebrated ornamental worldwide, thrives in semi-shaded growth environments in its natural habitat. This study utilizes Hydrangea macrophylla ‘Endless Summer’ as the experimental material to delve into its molecular mechanisms for adapting to semi-shaded conditions. Transcriptome analysis was conducted on leaves from four different natural light growth scenarios, showcasing phenotypic variations. From each sample, we obtained over 276,305,940 clean reads. Following de novo assembly and quantitative assessment, 88,575 unigenes were generated, with an average length of 976 bp. Gene ontology analysis of each control group elucidated the terms associated with the suitable environmental conditions for normal growth, development, and flowering, such as “reproductive bud system development” and “signal transduction”. The exploration of gene interactions and the identification of key genes with strong connectivity were achieved by constructing a protein–protein interaction (PPI) network. The results indicate that hydrangea grows vigorously and blooms steadily under semi-shaded conditions; the photosynthetic efficiency of hydrangea is stabilized through genes related to photosynthesis, such as PHYB, PSBR, FDC, etc. Hormone signal transduction genes like PIN3, LAX2, TIF6B, and EIN3 play important roles in responding to environmental stimulation and regulating growth and development, while genes such as SOC1, COL4/5/16, and AGL24 promote flowering. The expression of genes such as BGLUs and TPSs provides additional energy substances to support flowering.

Influence of mineral, organic, organomineral fertilization on winter hardiness components of columnar apple tree (<i>Malus domestica</i> Borkh.)

Intensive biological technologies of apple-tree cultivation with application of organic and mineral fertilizers form high nitrogen nutrition, thus leading to prolonged growth of fruit plants and reducing their winter hardiness. Columnar apple tree fail to demonstrate high potential for winter hardiness. Therefore, research into regularities and mechanisms behind the influence of nutritional status of columnar apple tree on indicators of plant winter hardiness is considered relevant. The research was aimed at establishing the influence of mineral, organic, organomineral fertilization on the components of winter hardiness of columnar apple trees grown on podzolic soil. Materials and methods. The research involved the ‘Triumph’, ‘President’, ‘Ostankino’ columnar apple varieties, as well as organic and mineral fertilizers. The experiment was conducted in 2016–2021 in the agrochemical experiment station of the Federal Horticultural Center for Breeding, Agrotechnology and Nursery (Moscow region) on podzolic soil of medium-loam particle size distribution. The experimental design included 4 variants: 1) control without fertilizers; 2) N90K90; 3) organic fertilizers 100 t/ha; 4) N90K90 organic fertilizers 100 t/ha. Naa (ammonium saltpeter), KCl mineral fertilizers were applied annually, organic fertilizer (horse manure with sawdust) was applied in 2014. Winter hardiness components and plant samples were analyzed according to generally accepted methods. According to the research into the influence of mineral, organic, organomineral fertilization on the components of winter hardiness of columnar apple tree (Malus domestica Borkh.) grown on podzolic soil in the conditions of the Moscow region, the fertilizer is found inefficient in terms of providing the optimal level of nitrogen nutrition of columnar apple tree plants, except for ‘Triumph’ variety when getting organic fertilizers at a dose of 100 t/ha. In January, fructose prevailed in the sugars of annual shoots of columnar apple tree plants. The ‘Triumph’ and ‘President’ varieties showed a tendency to increase in the content of fructose and glucose as compared with the control when getting organic fertilizers and their combination with mineral fertilizers. The same tendency was observed in the ‘Ostankino’ variety for the content of ascorbic acid in annual shoots, whereas this indicator of the ‘Triumph’ and ‘President’ varieties demonstrated the opposite trend. The ascorbic acid content in annual shoots in winter appeared consistent with its content in August shoots and remained independent on the content in leaves in August. With a decrease in temperature to -40 °C (component II of winter hardiness), the ‘Triumph ‘and ‘Ostankino’ varieties suffered reversible damage to the vegetative buds from 0 to 2.0 points, the ‘President’ variety introduced with 100 tons/ha organic fertilizers demonstrated an increase in damage to the vegetative buds to 3.17 points. The greatest damage to reproductive buds in the ‘President’ and ‘Ostankino’ varieties (3.85-3.91 on the control) was observed in component II of winter hardiness. The application of mineral and organic fertilizers increased these damages to complete death of reproductive buds. Injuries to bark, cambium in all variants of the studied varieties did not exceed 2.0 points. Wood appeared more damaged in the ‘Ostankino’ variety (up to 4.03 points in the combined application of N90K90 and 100 t/ha of organic fertilizers) as well as in the Triumph variety (up to 3.80 points in the N90K90 variant). As for component III of winter hardiness, an irreversible damage was noted for reproductive buds of the studied varieties in all variants of the experiment. In terms of component IV of winter hardiness, irreversible changes occurred in reproductive buds to the greatest extent (complete death in the ‘Triumph’ and ‘President’ varieties); in the tissue under reproductive buds, to the greatest extent in the ‘President’ variety (3.07 points in the variant of 100 tons/ha of organic fertilizers) and in the ‘Ostankino’ variety (2.76 points in N90K90), at the core, the maximum damage was noted in the N90K90 variant in the ‘Triumph’ (3.22 points) and ‘Ostankino’ (2.76 points) varieties.

Hydrogen Cyanamide Application Accelerates Vegetative Bud Break and Causes Earlier Yield in ‘Optimus’ and ‘Colossus’ Southern Highbush Blueberry

Southern highbush blueberry (Vaccinium corymbosum interspecific hybrid) cultivation is a major industry in subtropical regions where low winter temperatures are infrequent and inconsistent. In Florida and other subtropical areas, growers use hydrogen cyanamide (HC) applications during endodormancy to mitigate the negative effects of low chill accumulation. Hydrogen cyanamide is a synthetic plant growth regulator that increases and expediates dormancy release and budbreak. However, southern highbush blueberry cultivars differ in their sensitivity to HC. Optimus and Colossus are two recently released cultivars from the University of Florida blueberry breeding program. The effects of HC in these cultivars are unknown. This research aimed to describe responses to HC applications at different rates for these new varieties. Experiments took place in a commercial farm in Waldo, FL, on 3- to 4-year-old deciduous blueberry bushes. HC was applied at rates of 3.8 g·L−1 (0.38%), 5.1 g·L−1 (0.50%), and 6.4 g g·L−1 (0.63%) in ‘Optimus’ and 3.8 g·L−1 (0.38%), 5.1 g·L−1 (0.50%), 6.4 g·L−1 (0.63%), and 7.7 g·L−1 (0.75%) in ‘Colossus’. In both cultivars, the control treatment was not sprayed. Vegetative bud count, and flower bud development, flower bud mortality, and yield were determined. HC application thinned reproductive buds and increased vegetative budbreak. Although seasonal yield was not increased, HC advanced fruit ripening early in the season.

Wood age, rootstocks and cultivars drive the formation of productivity and fruit size in sweet cherry

To maintain the high yields and fruit quality necessary for profitability of sweet cherry production, it is important to consider precision crop load and canopy management techniques during limb renewal. The effects of branch section age, rootstock, and cultivar on spur and flower density and fruit quality have been discussed in previous studies, but most of them focus on a limited range of fruiting wood ages and scion-rootstock combinations. This study aims to analyse the processes of sweet cherry productivity and fruit size formation on a wide range of wood age to determine the limit after which branch preservation is not sustainable, and to evaluate the influence of rootstocks and cultivars on these parameters. The results indicate that wood age is one of the main drivers of productivity formation in cherry. The highest flower density was observed on 3-year-old branch sections – 324 flowers per linear m, due to high spur density, number of reproductive buds per spur and flowers per bud. Productivity on 2-year-old wood was also good (256 flowers per linear m), while a sharp decline in flower density was noted on 4- and 5-year-old wood. The largest fruits were formed on young branch sections, with a significant decline in fruit weight and diameter on 4- and 5-year-old sections. Rootstock vigour had a bigger effect on floral organ induction on 1-year-old shoots, than on spurs. Based on the results, it is advisable to regularly renew lateral branches older than 3 years to maintain high yield efficiency and fruit quality.

First recognition of the extinct eudicot genus Palibinia in North America: Leaves and fruits of Palibinia comptonifolia (R.W.Br.) comb. nov. from the Eocene of Utah and Colorado, USA

AbstractNewly investigated leafy twigs bearing axillary fruits from the Eocene Parachute Creek Member of the Green River Formation in eastern Utah, USA, have provided more information on the species previously attributed to the Proteaceae as Banksia comptonifolia R.W.Br. The leaves are simple, estipulate with short petioles, and elongate laminae with prominent angular nonglandular teeth. The laminae have a thick midvein and pinnate craspedodromous secondaries, and are distinctive in the presence of a thick, often coalified, marginal rim. Vegetative and reproductive buds occur in the axils of the leaves. These features indicate that the species belongs to Palibinia Korovin—an extinct Eudicot genus previously known only from the Paleogene of Asia and Europe. Small pedicellate ovoid fruits 1.5–2.2 mm wide are borne in fascicles of three and are seen to be capsules with four apical valves. Despite the specific epithet referring to similarity of the foliage to that of Comptonia (Myricaceae), the fasciculate inflorescence organization with axillary flowers is quite distinct from the catkins characteristic of that family. Assignment to Banksia or other Proteaceae with complex inflorescences and follicular fruits is also problematic. Additionally, MacGinitie′s transfer of the species to Vauquelinia of the Rosaceae is contradicted by the lack of stipule scars on the twig and by differences in leaf venation and floral morphology. We transfer the species to Palibinia comptonifolia (R.W.Br.) comb. nov., but its familial affinity within the Pentapetalae remains uncertain. This new occurrence augments records from the Paleogene of Turkmenistan, Kazakhstan, China, England, and Germany.

A new fossil Acmopyle with accessory transfusion tissue and potential reproductive buds: Direct evidence for ever-wet rainforests in Eocene Patagonia.

Acmopyle (Podocarpaceae) comprises two extant species from Oceania that are physiologically restricted to ever-wet rainforests, a confirmed fossil record based on leaf adpressions and cuticles in Australia since the Paleocene, and a few uncertain reports from New Zealand, Antarctica, and South America. We investigated fossil specimens with Acmopyle affinities from the early Eocene Laguna del Hunco site in Patagonia, Argentina. We studied 42 adpression leafy-shoot fossils and included them in a total evidence phylogenetic analysis. Acmopyle grayae sp. nov. is based on heterophyllous leafy shoots with three distinct leaf types. Among these, bilaterally flattened leaves uniquely preserve subparallel, linear features that we interpret as accessory transfusion tissue (ATT, an extra-venous water-conducting tissue). Some apical morphologies of A. grayae shoots are compatible with the early stages of ovuliferous cone development. Our phylogenetic analysis recovers the new species in a polytomy with the two extant Acmopyle species. We report several types of insect-herbivory damage. We also transfer Acmopyle engelhardti from the middle Eocene Río Pichileufú flora to Dacrycarpus engelhardti comb. nov. We confirm the biogeographically significant presence of the endangered West Pacific genus Acmopyle in Eocene Patagonia. Acmopyle is one of the most drought-intolerant genera in Podocarpaceae, possibly due to the high collapse risk of the ATT, and thus the new fossil species provides physiological evidence for the presence of an ever-wet rainforest environment at Laguna del Hunco during the Early Eocene Climatic Optimum.

Shoot growth pattern and return bloom of six olive varieties in response to cultivation practices stimulating or limiting the vegetative growth in young trees

Olive trees show a very marked alternate bearing behavior. Generally, this behavior is regulated by the balance between growth of vegetative and reproductive organs. A high fruit load can negatively affect the elongation of 1-year-old mixed shoots and lead to decreased production of new potential reproductive buds in the following year. Applied nutrients and water availability can also affect new shoot growth, yet, the best period for vegetative growth and bud induction is unclear. In this study we investigated growth pattern of the vegetative portion of 1-year-old mixed shoots (year n) and the return bloom in the following year (n + 1) in six olive cultivars under “strong” and “weak” vegetative growth practices. Results found that in the following year the number of inflorescences on 1-year-old mixed shoots was affected as a consequence of the different level of vegetative growth. In addition to the greater vegetative growth of 1-year-old mixed shoots, the number of sylleptic shoots also seemed to be influenced by cultivation practices. Moreover, sylleptic shoots had more inflorescences per bud than the 1-year-old shoots. The nodes of the 1-year-old mixed shoots that grew during June and July produced the majority of inflorescences per bud compared to the nodes that grew during spring and late summer.

Metabolomics and genetics of reproductive bud development in Ficus carica var. sativa (edible fig) and in Ficus carica var. caprificus (caprifig): similarities and differences.

In figs, reproductive biology comprises cultivars requiring or not pollination, with female trees (edible fig) and male trees (caprifig) bearing different types of fruits. Metabolomic and genetic studies may clarify bud differentiation mechanisms behind the different fruits. We used a targeted metabolomic analysis and genetic investigation through RNA sequence and candidate gene investigation to perform a deep analysis of buds of two fig cultivars, 'Petrelli' (San Pedro type) and 'Dottato' (Common type), and one caprifig. In this work, proton nuclear magnetic resonance (1H NMR-based metabolomics) has been used to analyze and compare buds of the caprifig and the two fig cultivars collected at different times of the season. Metabolomic data of buds collected on the caprifig, 'Petrelli', and 'Dottato' were treated individually, building three separate orthogonal partial least squared (OPLS) models, using the "y" variable as the sampling time to allow the identification of the correlations among metabolomic profiles of buds. The sampling times revealed different patterns between caprifig and the two edible fig cultivars. A significant amount of glucose and fructose was found in 'Petrelli', differently from 'Dottato', in the buds in June, suggesting that these sugars not only are used by the ripening brebas of 'Petrelli' but also are directed toward the developing buds on the current year shoot for either a main crop (fruit in the current season) or a breba (fruit in the successive season). Genetic characterization through the RNA-seq of buds and comparison with the literature allowed the identification of 473 downregulated genes, with 22 only in profichi, and 391 upregulated genes, with 21 only in mammoni.

Rootstock-mediated carbohydrate metabolism, nutrient contents, and physiological modifications in regular and alternate mango (Mangifera indica L.) scion varieties.

Most of the popular scion varieties of mango possess alternate/irregular bearing. There are many external and internal factors assigned, among them carbohydrate reserves, and nutrient content plays important roles in the floral induction process in many crop species. In addition to that rootstock can alter the carbohydrate reserve and nutrient acquisition of scion varieties in fruit crops. The present investigation was carried out to understand the effect of rootstocks on the physiochemical traits of leaf, and bud and nutrient content in regular and alternate bearing varieties of mango. The rootstock "Kurukkan" promoted starch content in leaves of both alternate bearing varieties 'Dashehari' (5.62 mg/g) and regular 'Amrapali' (5.49 mg/g) and encouraged higher protein content (6.71 mg/g) and C/N ratio (37.94) in buds of alternate bearing 'Dashehari'. While Olour rootstock upregulated the reducing sugar in leaves of 'Amrapali' (43.56 mg/g) and promoted K (1.34%) and B (78.58 ppm) content in reproductive buds of 'Dashehari'. Stomatal density in 'Dashehari' scion variety was found higher on Olour rootstock (700.40/mm 2), while the rootstock fails to modify stomatal density in the scion variety regular bearer 'Amrapali'. Further, a total of 30 carbohydrate metabolism-specific primers were designed and validated in 15 scion/rootstock combinations. A total of 33 alleles were amplified among carbohydrate metabolism-specific markers, which varied from 2 to 3 alleles with a mean of 2.53 per locus. Maximum and minimum PIC value was found for NMSPS10, and NMTPS9 primers (0.58). Cluster analysis revealed that scion grafted on Kurukkan rootstock clustered together except 'Pusa Arunima' on Olour rootstock. Our analysis revealed that Fe is the key component that is commonly expressed in both leaf and bud. Although Stomatal density (SD) and Intercellular CO2 Concentration (Ci) are more specific to leaf and Fe, B, and total sugar (TS) are abundant in buds. Based on the results it can be inferred that the physiochemical and nutrient responses of mango scion varieties are manipulated by the rootstock, hence, the scion-rootstock combination can be an important consideration in mango for selecting suitable rootstock for alternate/irregular bearer varieties.

Examining spray-induced gene silencing for pollen beetle control

Pollen beetles are a transcontinental threat to oilseed rape cultivation. Conventional insecticide use has resulted in resistance development, and can furthermore lead to losses of non-target organisms, including those that contribute to natural biological control of pollen beetle populations. Biosafe alternatives to synthetic pesticides must be explored. Double-stranded RNA (dsRNA) targeting pollen beetle, by the RNA interference (RNAi) mode of action, has been previously demonstrated under laboratory conditions. The present study examined, under a whole plant context, the potential for spray-induced gene silencing (SIGS) in pollen beetle. We confirmed translocation of sprayed dsRNA to later-emerging, non-sprayed dietary tissues of oilseed rape, as well as infiltration of sprayed dsRNA to the inner tissues of reproductive buds (pollen beetle’s food source). No effect on survival was observed. The inefficacy of SIGS observed here highlights the requirement for more effective SIGS approaches to pollen beetle management. The translocation of sprayed dsRNA within oilseed rape plants, and the non-significant yet detectable effect on target mRNA downregulation, together suggest potential for future optimization of a SIGS approach against pollen beetle.

Allometry of bud dynamic pattern and linkage between bud traits and ecological stoichiometry of Nitraria tangutorum under fertilizer addition.

Affected by the pressure and constraints of available resources, plant growth and development, as well as plant life history strategies, usually vary with environmental conditions. Plant buds play a crucial role in the life history of woody plants. Nitraria tangutorum is a common dominant woody species in desertified areas of northern China and its growth is critical to the desert ecosystem. Revealing the allometry of N. tangutorum aboveground bud fates and the linkage between bud traits and plant nutrient contents and stoichiometric ratios can be useful in understanding plant adaptation strategy. We applied seven nitrogen and phosphorus fertilizer addition treatments to natural N. tangutorum ramets in Ulan Buh Desert in three consecutive years. We surveyed three types of aboveground buds (dormant buds, vegetative buds, and reproductive buds) in each N. tangutorum ramet, then measured the plant carbon (C), nitrogen (N), and phosphorus (P) contents and ratios during three consecutive years. We specified that reserve growth potential (RGP), vegetative growth intensity (VGI) and sexual reproduction effort (SRE) are the three indices of bud dynamic pattern. The results showed that the bud dynamic pattern of N. tangutorum ramets differed significantly among different fertilizer addition treatments and sampling years. The allometry of RGP, VGI, and SRE was obvious, showing size dependence. The allometric growth relationship fluctuated among the sampling years. The linkage between bud traits and plant stoichiometric characteristics of N. tangutorum ramets showed close correlation with plant P content, C:P and N:P ratios, no significant correlation with plant C content, N content and C:N ratio. These results contribute to an improved understanding of the adaptive strategies of woody plants growing in desert ecosystems and provide insights for adoption of effective measures to restore and conserve plant communities in arid and semi-arid regions.

Genome-wide Transcriptome Analysis Reveals the Gene Regulatory Network in Star Fruit Flower Blooming

The star fruit is a perennial woody fruit tree, which can blossom and bear fruit many times a year. The time and quantity of flowering are the key indicators of its economic value. However, the flowering molecular mechanism of star fruit is still unknown. This study provides a genome-wide analysis of the key flowering genes of star fruit. Based on a previous morphological study of flower bud differentiation, the reproductive buds, vegetative buds and mature leaves of star fruit were sampled for transcriptome analysis. The results showed that the expression of GI, COL4, COL5, FT, FCA, FVE, PIF4, LFY, SVP-like, AP1 and FUL was correlated with floral induction and transition. The expression of TFL1, SVP-like genes (Yangtao2015203 and Yangtao2021074) was correlated with the inhibition of floral transition. Thus, we proposed a putative network of flower blooming in star fruit. This study provides useful information for investigating the genetic mechanism of flowering in star fruit and other perennial woody fruit trees.

Plant sex changes the outcome of ant–plant interactions in a facultative myrmecophytic cactus

Abstract In exchange for extrafloral nectar, ants deter herbivores from the plants decreasing the herbivore damage, and increasing plant performance in terms of growth and survival. Plants of different sexes may exhibit differences in the investment of resources for defence, thereby differentially decreasing the amount of energy available to other physiological processes. In this context, little is known about sex‐related differences in the outcome of ant–plant interactions in plants bearing extrafloral nectaries (EFNs). In the present study, we conducted ant‐exclusion experiments in the field to test for sex‐related differences in the outcome of ant–plant interactions in vegetative and reproductive buds of Opuntia robusta in individuals of different sexes in two populations: trioecious and dioecious. We applied tanglefoot to some plant and others were allowed ant access, and measured herbivory, relative growth rates and survival probabilities of buds during the growing season when EFNs are active. We counted the number of ants foraging in EFNs of flowers and cladodes of different sexes. We hypothesized that differences in resource investment to defence between sexes change the outcome of ant–plant interactions in terms of the number of ants foraging on EFNs, herbivory, growth, and survival probabilities. Our results suggest sex‐specific strategies in the investment of resources for defence mediated by EFNs in O. robusta, wherein males, females and hermaphrodites from both populations respond differentially to ant presence and herbivores. These sex‐related differences affected the outcome of the ant–plant interactions, influencing changes in number of ants foraging on EFNs, and the resulting herbivory, growth and survival of flowers and cladodes among the different sexes and among populations. Our results suggest that the maintenance of EFNs in O. robusta is costly, reflecting some trade‐offs between growth/survival and defence. Buds visited by ants tended to grow slowly and survive worse in the trioecious population; in the dioecious population they grew slower but survived better. Overall, a greater number of ants visiting EFNs was related to lower herbivore damage, greater growth and survival of flowers and cladodes. Our study underscores the importance of considering plant sex in the outcome of ant–plant interactions. Read the free Plain Language Summary for this article on the Journal blog.

Histological Studies in Vegetative and Reproductive Mango Buds

The present study was conducted on ten mango cultivars namely Alphonso, Bangalora, Kalepad, Himayuddin, Sendura, Mulgoa, Neelum, Rumani, Banganapalli and Swarnarekha and seasons are main and off-season at Kanyakumari and Tenkasi. The stem along with bud sample was collected during the month of October and November and conducted to examine the relation between internal structure of leafy and reproductive bud. During main season. Among ten mango cultivars, Bangalora and Swarnarekha have well developed at kanyakumar during main season for stage I, whereas Tenkasi, Alphonso and Bangalora well developed buds during the main season in stage I was observed. During off-season observed at kanyakumari Neelum and Alphonso had well developed for vegetative bud in stage I. At Tenkasi cultivars Kalapad and Bangalora had well developed for vegetative bud in stage I. The climatic factors prevailing at Kanyakumari during the main and off seasons for the months of August to September low temperature (190C to 210C) and high humidity (85 to 90%) and main season for the month of October to November, low temperature (210C to 230C) and humidity (80 to 85%). Whereas reproductive stage observed mango cultivars, Alphonso, Bangalora, Kalapad, Neelum and Swarnarekha had well developed reproductive buds in stage II & III during main season at kanyakumari. During off-season, cultivars of Himampasand, Kalapad, Alphoso, Neelum and Swarnarekha had well developed reproductive bud for stag II & III was favoured different stages of bud differentiation in the ten cultivars of mango.

Olive Bud Dormancy Release Dynamics and Validation of Using Cuttings to Determine Chilling Requirement.

Dormancy release dynamics in olive tree (Olea europaea L.) reproductive buds as affected by cold accumulation, tree bearing status, and budburst temperature was studied under natural and controlled conditions, using both cuttings and container- and field-grown plants. The chilling necessary for dormancy release was acquired at different times within the bud population, presenting a progressive pattern of reproductive budburst. Once sufficient chilling is accumulated, 20 °C is a suitable temperature for reproductive budburst, although higher temperature, e.g., 30 °C, during dormancy release can inhibit budburst. While the bearing status of trees determined the amount of return bloom, dormancy release followed a similar pattern for previously bearing and non-bearing trees. Concurrent with investigating budburst factors, the use of shoot cuttings was tested as a method for olive dormancy release studies by contrasting with results from whole trees. It was found it to be valid for studying reproductive budburst, thus providing a useful method to screen chilling requirements in cultivar evaluation and the breeding programs currently ongoing in this species. However, the method was not valid for vegetative budburst, with varying results between cuttings and the whole plant.

Internal freezing and heat loss of apple (Malus domestica Borkh.) and sweet cherry (Prunus avium L.) reproductive buds are decreased with cellulose nanocrystal dispersions.

Cold damage has caused more economic losses to fruit crop growers in the U.S. than any other weather hazard, making it a perennial concern for producers. Cellulose nanocrystals (CNCs) represent a new generation of renewable bio-nanomaterials, with many unique physical and chemical properties, including their low thermal conductivity. Our team has developed a process for creating CNC dispersions that can be sprayed onto woody perennial crops, forming a thin insulating film around buds which has been shown to increase cold tolerance. Using digital scanning calorimetry (DSC) on dormant apple (Malus domestica Borkh.) reproductive buds, we investigated the thermodynamic properties of plant materials treated with CNC dispersion at lower temperatures. Scanning electron microscopy (SEM) was used to evaluate the thickness of the CNC films and their deposition on the sweet cherry bud surface. Apple buds treated with 3% CNC exhibited lethal freezing at temperatures 3.2°C and 5.5°C lower than the untreated control when sampled 1 and 3 days after application, respectively. Additionally, the latent heat capacity (J/g) of the 3% CNC-treated buds was 46% higher compared with untreated buds 1 day after application, and this difference increased 3 days after application to 168% higher. The emissivity of cherry buds treated with 3% CNC was reduced by an average of 16% compared with the untreated buds. SEM was able to detect the dried films on the surface of the buds 3 days after application. Film thickness measured with SEM increased with material concentration. The emissivity, HTE, and LTE results show that CNC-treated reproductive buds released thermal energy at a slower rate than the untreated buds and, consequently, exhibited internal ice nucleation events at temperatures as much as 5.5°C lower. The increased enthalpy during the LTE in the CNC-treated apple buds shows more energy released at lethal internal freezing, indicating that CNC coatings are increasing the amount of supercooled water. The effects of CNC shown during the DSC tests were increased by CNC concentration and time post-application. These results suggest that CNC dispersions dry into nanofilms on the bud surface, which affects their thermodynamic processes at low temperatures.

Selection of a breeding source material in the collection of the walnut <i>(Juglans regia L.)</i> of the Main Botanical Garden RAS

The article considers the possibility of walnut cultivation in the Moscow region - in conditions far from its ecological optimum. The studies were carried out in 2013-2021 on the experimental site of the department of flora of the Main Botanical Garden of RAS, where in 1977 Alexei Konstantinovich Skvortsov established a collection of walnuts. The material for planting was the seed progeny of varieties and forms from various cities, including Moscow. The purpose of this work was the selection of promising forms for the creation of varieties adapted to the conditions of central Russia. The criteria for selecting the best genotypes were: winter hardiness, frost resistance, precocity, earlier entry into fruiting, autogamous type of flowering, lateral type of fruiting, fruits in the clusters, restraint in growth and high commercial qualities of fruits. As a result of the phenological observations, it was revealed that acclimatized walnut plants go through a full cycle of seasonal development, start the growing season late (April 29 − May 6) and end it early (October 1−11). The shoots are completely woody before the onset of cold weather, so the plants are quite winter-hardy in ordinary mild winters. The critical temperature in Moscow was -29.9 °C in January 2017. Low temperatures caused the death of reproductive buds, annual and perennial wood in almost all trees, and the most weakened specimens fell out completely. To date, the walnut gene pool is represented by 87 specimens aged from 37 to 44 years, of which 47 are single-stemmed and multi-stemmed trees and 40 are bushes. Samples were noted that, after the winter of 2017, normally bloomed and formed single fruits, despite the fact that the summer of 2017 was the coldest in the 21st century. As a result of studying the created genetic collection, 12 promising forms were identified. They are characterized by the presence of several breeding-valuable traits and regularly bear fruit. Further vegetative reproduction and varietal testing of the selected material is planned, which will allow solving a number of breeding and production problems to create a local range of walnuts.