Columnar Trees Research Articles

Chemical screening of inhibitors specific for MdDOX-Co that cause an apple columnar tree-shape.

MdDOX-Co, the ectopic expression of which is considered to cause the apple columnar tree shape, belongs to the 2-oxoglutarate-dependent dioxygenase (2ODD) family. It adds a hydroxyl group to position 12 of gibberellins (GAs). However, the 2ODD enzymes related to GA biosynthesis and catabolism are phylogenetically distinct from MdDOX-Co. Thus, it is possible that substrates other than GAs exist in MdDOX-Co. To identify the previously unidentified substrate(s) of MdDOX-Co, we searched for MdDOX-Co-specific inhibitors. Chemical screening using gas chromatography-mass spectrometry was performed to investigate the effects of 2400 compounds that inhibited the catalytic reaction of MdDOX-Co, but not the catabolic reaction of GA 2-oxidase, an enzyme involved in GA catabolism. By applying two positive compounds in Arabidopsis, a chemical 3-((2-chloro-6-fluorobenzyl)thio)-5,7-dimethyl-5H-pyrazolo[3,4-e][1,4,2]dithiazine-1,1-dioxide designated as TPDD that did not inhibit GA biosynthesis was selected. The structure-activity relationships among the TPDD analogs were also obtained.

Breeding columnar apple-tree cultivars for supercompact growth habit

This work was based on the combinatorial breeding technique using donors of the columnar growth type (Co gene), sources of winter hardiness and high consumer qualities, and scab immunity donors (Rvi6 gene). The selection in the columnar apple-tree hybrid progeny was accompanied by the assessment of growth vigor, compactness degree, and seedling cultivability in accordance with the guidelines.Due to the increasing popularity of apple trees with the columnar crown type, the volume of breeding work for columnar growth habit at the Russian Research Institute of Fruit Crop Breeding (VNIISPK) over the past 9 years amounted to 133,582 flowers, or one third of the entire hybridization envisaged by the apple-tree breeding program. Meticulous selection of parent forms is carried out in order to incorporate a set of useful traits in the columnar growth habit genotype. Both cultivars and hybrid forms serve as sources and donors of the traits interesting for breeders. All the studied cultivars released by VNIISPK are dwarf: their height is within the range from 287 cm (cv. ‘Priokskoe’) to 198 cm (cv. ‘Orlovskaya Yesenia’), and they can be recommended for both commercial plantations and amateur gardens. The columnar form 34-34-98 is characterized by a unique degree of compactness (the ratio of the internode length to the shoot diameter) equal to 0.4 versus the average value of 1.6 for this indicator in the studied columnar cultivars. This form was involved in the release of 78 promising hybrid seedlings, the best of which (38.5%) were transferred to the garden for primary variety trials. A large yield of seedlings characterized by high compactness in the progeny of the columnar apple tree 34-34-98 makes it possible to recommend it for the development of new apple-tree genotypes for highly cost-effective orchards with high tree planting density.

Apple cultivars and rootstocks assay for the identification of diverse viruses and healthy genotypes for breeding

The prevalence of harmful viruses, viz., apple stem grooving virus (ASGV), apple stem pitting virus (ASPV), apple chlorotic leaf spot virus (ACLSV), apple mosaic virus (ApMV), and tomato ringspot virus (ToRSV) in apple tree plantations in the Ryazan, Yaroslavl, and Moscow regions, Russian Federation, based on genotype features, planting type (industrial, collection, and repository), and tree age was studied during 2018–2021. The prevalence of harmful and latent viruses ranged from 49.6% to 53.8% in apple cultivars and from 8.3% to 100% in apple clonal rootstocks. The most common virus in the Moscow and Yaroslavl regions was ACLSV (34.7% and 53.8%) and that in the Ryazan region was ApMV (33.3%). Relative to that in young apple trees, the virus influence in older tree tissues was higher by 20% to 43% depending on virus type. Monoviral infection prevailed (59% of all trees were infected with one virus) in the studied apple tree cultivars. Of the cultivars, 25% were infected by a complex of two viruses (ASPV + ACLSV), 10% were infected by three viruses, and 6% were infected by four viruses. The highest prevalence of latent viruses was observed in old Russian cultivars (53.5%) and selections from old foreign cultivars (57.2%). Virus occurrence was slightly lower (51.6%) in new Russian cultivars than in other cultivars. Columnar apple tree cultivars had the lowest virus occurrence (30%) and were found to be more tolerant than other genotypes. The highest virus incidence was recorded in industrial orchards (63.4%), followed by that recorded in collection (20.8%) and repository (18.3%) plantations. By using ELISA, the apple genotypes that were free from harmful viruses were identified as source plants, i.e., 183 plants from 18 apple tree cultivars and 131 plants from clonal rootstocks. Results indicated that virus-free apple germplasm is highly effective for the successful implementation of breeding and genetic improvement.

Tree architecture of columnar apple tree genotypes

Tree architecture of columnar apple tree genotypes

Evaluation of economically valuable traits of the columnar variety Poesia and the prospects of its use in breeding

One of the most promising forms of apple trees for super-intensive gardens on a new genetic basis is the columnar apple tree. Within the framework of the breeding program of the Russian Research Institute of Fruit Crop Selection, 5 columnar apple tree varieties were created and released, one of which is the Poesia variety. The article presents an assessment of the suitability of the columnar apple tree variety Poesia for intensive gardening and prospects of its use in breeding work to create competitive varieties of the new generation. According to complex of economically valuable traits, the variety is characterized by winter-hardiness, early maturation, high yield – for the first 7 years of fruiting, the average variety yield on dwarf rootstock 62–396 was 41.6 t/ha, immunity to scab (gene Rvi6), greatly reducing the pesticide load in the garden. The fruits have an attractive appearance, which is rated with 4.4 points (on a five-point scale), sweet and sour taste (4.3 points). It was established that the Poesia variety is a donor of columnar shape (Co gene) and immunity to scab (Rvi6 gene). With its participation, eight selected forms and one elite seedling have already been created.

Influence of mineral fertilizers on potash nutrition and productivity of columnar apple

The columnar form of apple tree is promising for growing in super-intensive orchards. The mineral nutrition study of apple tree with columnar crown is relevant due to high density of tree planting. The article presents the study results on the effect of mineral fertilizers on potash nutrition and the yield of columnar apple tree. The experiments were carried out in an experimental orchard located in the forest-steppe zone of the Central Russian Upland (Oryol region). The soil of the orchard is loamy haplic Luvisol with a high content of organic matter. Fruit plantations are represented by columnar apple trees of Poezia variety on 62-396 rootstock planted in 2016. Urea ((NH2)2CO) and potassium sulfate (K2 SO4) were used as fertilizers in doses of N60K80; N90K120; N120K160 which were introduced in early spring. The content of exchange potassium in the soil was determined annually in layers (0-20 cm and 20-40 cm), the concentration of potassium in leaves and fruits, yield. The use of fertilizers contributed to an increase in the exchange potassium content in the soil both in the 0-20 cm layer (45 - 53%) and in the 20-40 cm layer (18-31%). The amount of potassium in leaves and fruits also increased. However, potassium concentration in the leaves (0.77 … 0.95% dry matter) remained significantly below the optimum (1.5% dry matter). A significant increase in the average fruit weight was revealed in options N90K120 and N120K160.

The apple gene responsible for columnar tree shape reduces the abundance of biologically active gibberellin.

Ectopic expression of the apple 2-oxoglutarate-dependent dioxygenase (DOX, 2ODD) gene, designated MdDOX-Co, is thought to cause the columnar shape of apple trees. However, the mechanism underlying the formation of such a unique tree shape remains unclear. To solve this problem, we demonstrated that Arabidopsis thaliana overexpressing MdDOX-Co contained reduced levels of biologically active gibberellin (GA) compared with wild type. In summary: (i) with biochemical approaches, the gene product MdDOX-Co was shown to metabolize active GA A4 (GA4 ) to GA58 (12-OH-GA4 ) in vitro. MdDOX-Co also metabolized its precursors GA12 and GA9 to GA111 (12-OH-GA12 ) and GA70 (12-OH-GA9 ), respectively; (ii) Of the three 12-OH-GAs, GA58 was still active physiologically, but not GA70 or GA111 ; (iii) Arabidopsis MdDOX-Co OE transformants converted exogenously applied deuterium-labeled (d2 )-GA12 to d2 -GA111 but not to d2 -GA58 , whereas transformants converted applied d2 -GA9 to d2 -GA58 ; (iv) GA111 is converted poorly to GA70 by GA 20-oxidases in vitro when GA12 is efficiently metabolized to GA9 ; (v) no GA58 was detected endogenously in MdDOX-Co OE transformants. Overall, we conclude that 12-hydroxylation of GA12 by MdDOX-Co prevents the biosynthesis of biologically active GAs in planta, resulting in columnar phenotypes.

Cockles, Mussels, Fishing Nets, and Finery: The Relationship between Cult, Textiles, and the Sea Depicted on a Minoan-Style Gold Ring from Pylos

AbstractThe Griffin Warrior Ring No. 2 is a gold Minoan-style engraved signet ring from Pylos dating to the Late Helladic IIA (1580–1490 BCE). The ring's bezel depicts a seascape with a columnar tree shrine flanked by palm trees situated on a rocky outcrop. Five elaborately dressed female figures stand on either side of the shrine. The tree shrine features a net pattern in the space between its stone or brick piers. I argue that this represents a fishing net and that the structure is a sea altar dedicated to an unnamed Minoan tree deity. The ring's hoop is decorated with cockleshells, further emphasizing its marine theme. I propose that the iconography alludes to marine food resources, practical and luxury textile fibers, sea trade, transculturality, and cult and is testament to the importance of the sea in the Aegean Bronze Age.

A rapid real‐time PCR assay for detecting columnar growth in apples (Malus × domestica)

AbstractColumnar growth in apples can have considerable positive consequences for orchard maintenance, but the lack of columnar cultivars producing fruits with desired market quality prevents their broader utilization in orchards. New crossings focused on their breeding are therefore conducted throughout the world every year. Unfortunately, the reliable discrimination between columnar growth and normal phenotype is difficult until seedlings are 2–3 years of age. However, molecular marker–assisted selection (MAS) can be used in seedlings several weeks old providing immense help in breeding programmes focused on columnar apple production. Here, we describe a rapid and reliable method for the detection of both wild‐type (WT) and columnar (Co) alleles originating from ‘McIntosh Wijcik’ in a single reaction using a real‐time PCR allelic discrimination approach. Our assay was tested in 130 genotypes (80 normal and 50 columnar habit) from various crossings and their parents, and in all cases, genotype corresponded to phenotype. The assay is thus suitable for laboratories interested in high‐throughput MAS for columnar tree habit breeding.

Growing technology of crowned trees of columnar apple cultivars at Russian research institute of fruit crop breeding

Relevance. Selection of columnar apple cultivars and development of adapted elements of their cultivation technology are one of the promising areas of the research work of the Russian Research Institute of Fruit Crop Breeding. The result of 36 years of the target selection work was the creation of 5 columnar apple cultivars accepted in the State Register of breeding achievements: ‘Priokskoye’, ‘Poezia’, ‘Vostorg’, ‘Girlianda’ and ‘Orlovskaya Yesenia’. All cultivars are characterized by high precocity, productivity and immunity to scab. The special habit of the columnar shape of the apple tree determines a special type of planting that is characteristic only for it, providing for super-dense placement of trees.Results. Our research experimentally demonstrates the possibility of reducing the total number of plants per hectare while maintaining a high density of fruit wood in the orchard. These technologies will significantly reduce the amount of necessary planting material, therefore, reduce the initial cost of laying a columnar apple orchard. Thus, when growing columnar cultivars in the crown of a 3–4-98 semi- dwarf rootstock with a tree planting density of 3333 trees per hectare, the number of columnar branches corresponds to the plantation with a density of 20,000 columnar trees per 1 ha. The study of this technology showed that the cultivars entered fruiting in the third year after grafting of 2-year-old skeletal trees; the yield of the studied columnar cultivars for the first 10 years of fruiting averaged 81.6 t/ ha. Annual fruiting was observed throughout the entire observation period. Another promising option is to grow columns in the form of crowned plants on a dwarf rootstock 62–396. The crown on average consists of 5 branches, while the total number of columnar branches reaches 12 500 PCs/ha. The proportion of trees that entered fruiting in the third year after grafting depended on the depth of seedling planting. For normal planting, it was 28%, which is twice the same value for deep planting (15 cm below the root neck).

Columnar growth phenotype in apple results from gibberellin deficiency by ectopic expression of a dioxygenase gene.

The apple cultivar McIntosh Wijcik, which is a mutant of 'McIntosh', exhibits a columnar growth phenotype (short internodes, few lateral branches, many spurs, etc.) that is controlled by a dominant Co gene. The candidate gene (MdDOX-Co), encoding a 2-oxoglutarate-dependent dioxygenase, is located adjacent to an insertion mutation. Non-columnar apples express MdDOX-Co in the roots, whereas columnar apples express MdDOX-Co in the aerial parts as well as in the roots. However, the function of MdDOX-Co remains unknown. Here, we characterized tobacco plants overexpressing MdDOX-Co. The tobacco plants showed the typical dwarf phenotype, which was restored by application of gibberellin A3 (GA3). Moreover, the dwarf tobacco plants had low concentrations of endogenous bioactive gibberellin A1 (GA1) and gibberellin A4 (GA4). Similarly, 'McIntosh Wijcik' contained low endogenous GA4 concentration and its dwarf traits (short main shoot and internodes) were partially reversed by GA3 application. These results indicate that MdDOX-Co is associated with bioactive GA deficiency. Interestingly, GA3 application to apple trees also resulted in an increased number of lateral branches and a decrease in flower bud number, indicating that gibberellin (GA) plays important roles in regulating apple tree architecture by affecting both lateral branch formation (vegetative growth) and flower bud formation (reproductive growth). We propose that a deficiency of bioactive GA by ectopic expression of MdDOX-Co in the aerial parts of columnar apples not only induces dwarf phenotypes but also inhibits lateral branch development and promotes flower bud formation, and assembly of these multiple phenotypes constructs the columnar tree form.

Сорта яблони селекции ВНИИСПК как источники и доноры хозяйственно ценных признаков

Brief descriptions of economically valuable characteristics of 45 apple varieties breeding in All-Russian Research Institute of Fruit Crop Breeding are given in this article. Long-term study of varieties allowed to revealed from a large set of varieties donors and sources of valuable traits. The varieties Afrodita, Bolotovskoe, Veniaminovskoe, Vostorg, Zdorovie, Ivanovskoe, Kandil Orlovsky, Kurnakovskoe, Orlovskoe Polesie, Pamiati Hitrovo, Svezhest, Sozvezdie, Solnyshko, Stroevskoe and Jubiley Moskvy have been selected as donors of immunity to scab. The varieties Vostorg, Girlianda, Orlovskaya Yesenia, Poezia and Priokskoe have been selected as donors of columnar tree habit. The varieties Bolotovskoe, Veteran, Girlianda, Imrus, Orlik, Ranneye Aloe, Sozvezdie, Sokovinka and Yubiley Moskvy can be sources of higher winter hardiness. Columnar apple varieties of the Institute as well as Veteran, Svezhest and Utrennya Zvezda are sources of high productivity. The varieties Blagodat, Zhelannoe, Morozovskoe, Orlovskoe Polosatoe, Pamiat Voinu and Slavianin are high marketable qualities of fruit; the varieties Afrodita, Blagodat, Veniaminovskoe, Veteran, Orlik, Osipovskoe, etc. are high taste qualities of fruit; Veteran, Imrus, Kulikovskoe and Svezhest are durable fruit storage; the varieties Zarianka, Pepin Orlovsky, Veteran, Ivanoskoe and Vita are higher content of ascorbic acid in fruit (14,5-21,4 mg/100 g); the varieties Afrodita, Radost Nadezhdy, Bolotovskoe, Vita, Kandil Orlovsky, Pamiati Hitrovo, Pamit Semakinu, Utrenya Zvezda and Chistotel are high content of P-active substances in fruit (over 450 mg/100 g); the varieties Bolotovskoe, Orlovim, Orlinka, Osipovskoe, Priokskoe, Rozhdestvenskoe, Girlianda and Vostorg are sources of variety suitability for juice production. Some of these varieties have already been successfully used in Russia and a number of other countries as donors or sources for the creation of varieties of new generation.

Comparative Analysis of Load Adaptation Strategies in Columnar Cacti and Hardwood Trees

Abstract: “Cacti are different.” This sentence holds true for many aspects of the functional morphology and anatomy of cacti in comparison to other perennial plants. The biomechanical adaptations, especially of tree-like columnar cacti, seem to be unique. The scope of this small review is to elucidate some of their specific load adaptation strategies and how they deviate from — or are similar to — typical hardwood trees.

Evaluation of biennial bearing of apple genotypes with columnar tree growth habit

Evaluation of biennial bearing of apple genotypes with columnar tree growth habit

A four phase model for the macrosegregation and shrinkage cavity during solidification of steel ingot

A four-phase mixed columnar–equiaxed solidification model is introduced to calculate the formation of macrosegregation and shrinkage cavity during solidification of steel ingot. The four phases are the liquid melt, the solidifying solid with columnar morphology, the solidifying solid with equiaxed morphology, and the gas phase (or covering liquid slag). Multiphase/multiphysics transport phenomena (mass, momentum, species and enthalpy) are solved with a volume-average approach. Solidification induced mass and species transfers among metal phases are considered according to the thermodynamics and diffusion-governed crystal growth kinetics. The gas phase (or covering liquid slag) is only required to feed the shrinkage cavity and no mass/species exchange with other metal phases occurs. The following modeling results are obtained: the progress of columnar tip front and growth of columnar tree trunks, the nucleation and growth of equiaxed grains, the melt flow and equiaxed crystal sedimentation, the solute partitioning at the solid/liquid interface, the transport of the solute species and induced macrosegregation, the shrinkage cavity, the interaction or competition between growing columnar and equiaxed phases and the occurrence of columnar to equiaxed transition (CET). Those modeling capacities were verified by the calculation of a 10.5tons steel ingot. The experimentally determined profile of the shrinkage cavity, Sulfur print and chemical analysis of macrosegregation of the ingot in a vertical section were also available. Satisfactory agreement was obtained between the simulation and experimental result. Finally, a new hypothesis for the initialization of A-segregates is proposed: the motion of equiaxed phase and its interaction with the melt flow in the vicinity of growing columnar tip front lead to formation of an A-shape segregation band starting from the ingot corner just above the columnar-to-equiaxed transition area. This A-segregation band might provide a favored location for the initialization of A-segregates. Further dedicated experiment should be carried out to verify it.

Cherry tree growth models for orchard management improvement

Twelve cultivars and selections of sweet and sour cherries were surveyed and characterized agromorphologically. A total of 33 characters, mainly defined by the International Plant Genetic Resources Institute and the International Union for the Protection of New Cultivars of Plants, were used to describe the tree, branches, leaves, blooming, and fruits. This allowed unequivocally clear separation between six distinct growth forms-compact, dwarf, upright (pillar), columnar, weeping, and standard form-as well as evaluation of their interaction with four rootstocks of different vigor. Natural tree habit diversity within distinct growth forms has the potential to reduce pruning and training requirements in cherry, particularly in medium- and high-density planting. The reported unique growth forms, within compact and columnar tree habit of sour and sweet cherries, combine specific genetic potential of scion fruiting habits and vigor. Genetic diversity was confirmed by simple sequence repeats. Research showed that multiple interactions exist between rootstock and genotypic determined components of the tree architecture, namely branching density, shoot growth dynamics, flower bud differentiation, and distribution. Developed ideotypes are new foundational concepts of modern production strategies bringing significant contribution to improvement of cherry orchard training systems, light interception, efficient fruit harvest, and economics.

TOWARDS IDENTIFICATION OF THE GENE RESPONSIBLE FOR THE COLUMNAR PHENOTYPE OF 'MCINTOSH 'WIJCIK'' APPLE

The 'Wijcik' mutant of the apple cultivar 'McIntosh' shows columnar-type growth, characterized by altered branching and a thick stem. Instead of normal branches, spur-like branches are produced on 'Wijcik' trees, leading to apples produced close to the stem. Columnar-type growth is a desirable trait, as columnar apple trees need considerably less pruning compared to standard trees. Furthermore, apple picking and the application of chemicals is much easier on columnar trees. The genetic basis for columnar growth is a somatic mutation that results in dominant inheritance of the columnar growth trait. The columnar gene (Co) has been previously mapped on apple linkage group 10. Three adult segregating populations, with a total of 301 F1 plants, and two three-year old populations of 1,250 F1 plants were used for fine mapping of the Co region, using newly developed simple sequence repeat (SSR) markers that were designed based on the 'Golden Delicious' apple genome sequence. Co was found to cosegregate with SSR marker Co04R12 and the Co region was found to be delimited by SSR markers Co04R11 and Co04R13 corresponding to a genetic region of 0.56 cM and a genomic region of 393 kb in the 'Golden Delicious' genome. By using BAC libraries, we could identify the clones covering the Co region in 'McIntosh' and 'Wijcik'. This enabled us to sequence the complete Co region in both cultivars. Sequence comparison between 'McIntosh' and 'Wijcik' lead to the identification of a 1,956 bp insertion in 'Wijcik'. This work resulted in the development of a perfect marker for columnar growth for application in breeding, and, in the future, will result in better understanding of the physiological background of columnar growth and the availability of the Co gene for biotechnological applications to manipulate tree architecture.

Apple gene pool use, sources and donors of economically valuable traits

The significance of an apple genetic collection and its use in the development of new adaptive apple cultivars meeting up-to-date requirements are investigated. Nevertheless, the genetic diversity of existing collections is shown to be still insufficiently used in breeding institutions. McIntosh, Jonathan, Wealthy, Golden Delicious, Melba, Antonovka Obyknovennaya, Ranetka Purpurovaya, and Papirovka are valuable parental varieties in apple breeding, used in Russia and worldwide. In spite of the availability of a large genetic collection, only 48 cultivars were used as initial parental forms when developing about 50 apple varieties (according to the All-Russia Research Institute of Fruit Crop Breeding). That makes up less than 7% of the gene pool of over 700 cultivars kept at the Institute. Among 10 most valuable sources of new varieties are McIntosh (12), scab immune Seyanetz 814 (9), Antonovka Obyknovennaya (7), Papirovka Tetraploid (11), etc. We recommend sources and donors for apple breeding for commercially valuable traits (winter hardiness, columnar tree type, precocity and high productivity, long fruit storability, high resistance and immunity to scab), as well as donors of diploid gametes for triploid cultivar breeding, sources and donors of high contents of sugars, titrated acids and biologically active substances (ascorbic acid and P-active substances) in fruits. The necessity of selection and breeding of complex sources and donors possessing two and more valuable traits (immunity to scab and tetraploidy, immunity to scab and the columnar tree type, etc.) is discussed.

Synthesis, characterization and performance evaluation of three-layered photoanodes by introducing a blend of WO3 and Fe2O3 for dye degradation

A three-layered photoanode has been synthesized by the introduction of an additional layer of mixed WO3 and Fe2O3. A total of nine differently-packaged films were prepared by sol-gel method. The fabricated photoanodes were then successfully characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). A comparative study was also done to differentiate the films fabricated with WO3, Fe2O3 and their mixture. Compact, columnar tree and shallow patterns were observed on the cross cleavage of the synthesized layers. These distinct patterns were associated with the growth of layers which consequently led to unique surface morphologies. An increase in photocurrent density was observed on the bicomponent film which has been linked to a high degree of surface roughness as well as improved internal porosity. Three-layered photoanodes, modified with an additional bicomponent layer of WO3:Fe2O3 established much higher photocurrent outputs compared to that of nanostructured WO3 or Fe2O3, regardless of the bicomponent layer arrangement. However, with the bicomponent layer on top and middle, the measured photocurrent soared more than three times as much compared to a slight increase observed when the bicomponent was placed on the bottom.

Modification of leaf morphology and anatomy as a consequence of columnar architecture in domestic apple (Malus × domestica Borkh.) trees

A quantitative study has been made of the modifications to leaf morphology and anatomy evident in columnar apples trees when compared to standard ones, using the original cultivar and the first columnar mutant derived from it, as well as other closely and more distantly related cultivars. Significant increases in leaf number, area, weight per unit area, thickness and midrib angle, together with altered shape, have been recorded consistently for the leaves subtending the developing fruits of the columnar cultivars. Additionally, significant increases in leaf rolling, epicuticular wax, stomatal size and density and leaf chlorophyll content were recorded. Scanning electron microscopy revealed that columnar cultivars develop an additional layer of well-developed palisade mesophyll and a greater depth of spongy mesophyll when compared to their standard counterparts. This large-scale modification of leaf characteristics is considered in terms of the very open architectural phenotype of columnar trees and the impact this may have on the canopy microclimate that influences leaf development.