56 results about "Cambium" patented technology

The invention provides a method for grafting Tibetan white bark pine on Chinese pine, belongs to the technical field of needle-leaved tree species grafting, and solves the technical problem that the survival rate is lower than 40% due to slow joint healing, high pathogen infection rate and environmental fluctuation. According to the technical scheme, the method is characterized by comprising the following steps: cutting 1.8-2.2 cm of a vertical notch reaching xylem at the part, which is 2.5-3.5 cm exposed out of the surface of a culture medium, of a rootstock rhizome part; cutting the scion base into a symmetrical double-sided wedge shape, and immersing the scion base into a sodium citrate buffer solution containing polyvinylpyrrolidone, methyl salicylate and calcium chloride; the two sides of the vertical notch are coated with adsorption glue; inserting a scion alignment cambium and fixing by using a grafting belt; an ethanol water solution containing salicylic acid, trehalose and polysorbate 80 is applied to the interface every 2-3 days; maintaining the day temperature to be 23-25 DEG C, the night temperature to be 16-18 DEG C and the humidity to be 90-95%; when the young sprouts grow to 2-3 cm, the rootstocks are girdled, and trunks are cut off after 7-10 days. The method is used for large-scale breeding of the Tibetan pinus bungeana grafted seedlings.

The invention relates to the technical field of plant grafting, in particular to a method for improving the grafting survival rate of malania oleifera, which comprises the following steps: S1, scion preparation: treating branches of excellent perennial wild malania oleifera plants in the field, conveying the branches to an inoculation field, and disinfecting to obtain disinfected branches; s2, stock preparation; s3, grafting: preparing a scion by using the disinfected branch, treating a stock, tightening the stock and a grafting film for tongue grafting of the scion, and smearing a healing agent on a cut of the cut stock and the upper end of the grafting film; s4, management after grafting. Compared with the prior art, the method has the advantages that superior plant branches and artificially cultivated stocks are subjected to tongue grafting, and compared with bud grafting, the yield time of grafted seedlings is shortened; and then the branch of the malania oleifera superior plant is treated immediately when the scion is collected, so that the problems that the activity of the branch is reduced in the transportation process and the formation of the callus of the stock and scion cambium is slow are solved, the grafting survival rate is increased, and the grafted seedling obtaining time is shortened.

The invention discloses application of a ubiquitination gene E6-LIKE gene knockout NL895 poplar cv.' nalin895 'and a method of the ubiquitination gene E6-LIKE gene knockout NL895E6-LIKE gene knockout NL895E6-LIKE gene knockout NL895 poplar cv.' nalin895', a plant with the NL895E6-LIKE gene knockout is constructed through a CRISPR / CAS9 editing technology, the number of xylem layers in the knockout plant is remarkably increased, and the number of formed layers is also remarkably increased; the result shows that after the E6-LIKE is deleted, the stem cambium activity and xylem differentiation of the poplar are promoted, and the method has important significance on development and utilization of the poplar.

The invention discloses a Ilex rotunda grafting method which comprises the following steps: from late February to mid-March, preparing a 3-5-year-old Ilex rotunda rootstock for cultivation, and irrigating the Ilex rotunda rootstock; preparing a scion with double inclined planes; cutting a cut with the depth of 3cm in the rootstock, inserting the scion and aligning to the cambium; and carrying out double-layer binding by using a viscous PVC grafting film and a grafting soft film. The final-period management comprises the steps of sunshelter building, irrigation, bud picking, unbinding, pinching, fertilization and weeding. The problem that Ilex rotunda is difficult to breed is solved, the grafting survival rate is high, and the seedling raising period is short.

The invention discloses a method for improving the character of a poplar, which is characterized in that a poplar GLR3.3b gene is knocked out through a CRISPR / Cas9 system to obtain a gene knockout poplar. Compared with a wild type poplar, the widths of a gelatinous layer, xylem in a stem, a cambium and a cortex are increased in a stem cell wall of the gene knockout poplar, and the cellulose content is remarkably improved, so that wood has higher strength and tensile strength, and the mechanical property of the poplar is improved.

The invention relates to a method for inducing doubling cultivation of polyploidy by girdling calluses of camellia oleifera branches, the influence on tree vigor is reduced through girdling, the efficiency of regeneration buds is improved through thorough removal of cambium, the bottleneck in the prior art is overcome, chimera-free polyploidy material induction can be realized without in-vitro tissue culture, and the method is suitable for large-scale popularization and application. The method is simple and convenient to operate and low in cost, can effectively avoid the problems of rooting difficulty of tissue culture materials, transplanting loss of tissue culture seedlings and the like, provides a new technical approach for woody plant polyploid breeding, and has important popularization and application values.

The invention discloses a grafting method of a lantern tree, and relates to the technical field of plant grafting, and the main points of the technical scheme are that the grafting method comprises the following steps: S1, rootstock selection and treatment: selecting a pendant flower as a rootstock, cutting off the upper part of the rootstock, vertically and downwards cutting a notch on one side of the cross section of the rootstock, and forming a cut-grafting interface with the depth just reaching the xylem; s2, scion selection and treatment: selecting a lantern tree qualitative branch as a scion, cutting the scion into branch sections, cutting a long cut surface at the lower end of the scion by using a knife to expose a cambium, and cutting a short cut surface on the opposite side of the long cut surface to enable the lower end of the scion to be wedge-shaped; s3, grafting operation: inserting the pretreated long cut surface of the scion into a pre-cut vertical cut of the stock, so that the long cut surface of the scion is attached to a cambium on at least one side of the stock; a plastic film is wound upwards from the lower portion of the connector, and the combination portion of the stock and the scion is tightly bound and fixed and bagged. The invention fills up the blank of research in the field and is expected to cultivate a more heat-resistant lantern tree variety.

The invention discloses a method for improving the character of a poplar, which is characterized in that a poplar GLR3.3a gene and a poplar GLR3.3b gene are knocked out through a CRISPR / Cas9 system to obtain a gene knockout poplar. Compared with a wild type poplar, the widths of a gelatinous layer, xylem in a stem, a cambium and a cortex are increased in a stem cell wall of the gene knockout poplar, and the cellulose content is remarkably improved, so that wood has higher strength and tensile strength, and the mechanical property of the poplar is improved.

The utility model discloses tree layering propagation girdling equipment, and mainly relates to the field of tree layering propagation equipment. Comprising a girdling belt, a tightening assembly is arranged on the girdling belt, and the girdling belt is in butt joint and closed through the tightening assembly; the inner end face of the girdling belt is symmetrically provided with girdling tools, and after the girdling belt is closed in a butt joint mode through a tightening assembly, the girdling tools make contact with a cut tree. And the girdling belt is made of a soft deformable elastic material. The branch girdling device has the advantages that uniform girdling operation on the branch position can be achieved, a cambium exposed by cutting of the branch position subjected to girdling is smooth and consistent in exposure, it is guaranteed that the subsequent girdling position can normally root, and it is guaranteed that plants subjected to high-pressure layering can survive better.

This invention belongs to the field of rubber tapping technology and discloses a method, system, and medium for generating intelligent latex tapping operation trajectories. The method includes: acquiring X-ray images of living trees in a preset area; performing grayscale conversion and filtering on the X-ray images to obtain processed images; constructing a three-dimensional envelope model of the living tree based on the processed image, the three-dimensional envelope model of the living tree including a bark envelope model and a core-edge envelope model; generating a tapping trajectory based on the bark envelope model and the core-edge envelope model, the tapping trajectory including the bark cutting length, cutting direction, and cutting depth. This invention can accurately identify the boundaries between the latex layer and cambium layer of rubber trees, and then plan its own tapping trajectory through the three-dimensional envelope model of each rubber tree, realizing efficient and accurate intelligent rubber tapping operations.

This invention discloses a method for inducing and culturing burdock stem cells and stem cells, belonging to the field of plant biotechnology. Using burdock roots as explants, the cambium is determined by staining, and the cambium is obtained using enzymatic digestion. The cambium is then inoculated into a specific ratio of induction solid medium and cultured in the dark to efficiently induce primary stem cells. These primary stem cells are then transferred to a proliferation solid medium for subculture and selection to obtain and maintain a vigorous, soft stem cell line. The solid stem cell line is further transferred to a liquid medium for shaking culture to establish a suspension stem cell line. This invention provides high induction efficiency, stable stem cell characteristics, and good reproducibility, offering a high-quality starting material and technical platform for in vitro preservation of burdock germplasm, large-scale production of secondary metabolites, and genetic transformation.

The present invention discloses the application of the PdAKR2A gene in improving the photosynthetic rate and biomass of poplar, belonging to the technical field of poplar genetic engineering breeding. The present invention for the first time discloses that overexpression of the PdAKR2A gene can significantly increase the number of cambium cell layers and the width of xylem in poplar, thereby increasing the plant height and ground diameter of poplar, and thus improving the growth rate and biological yield of poplar; it can significantly increase the net photosynthetic rate, stomatal conductance, transpiration rate and chlorophyll content of poplar; it can significantly increase the lignin and cellulose contents of poplar; the provided PdAKR2A gene can be used as a candidate gene for cultivating new poplar varieties with faster growth rate and better quality, which is of great significance for promoting the sustainable development of forestry in China and alleviating the supply-demand tension in the wood market.

The invention discloses an application of a transmembrane protein gene (TRANSMEMBRANE, TRM) for knocking out Popus deltoids * P.eurameracana cv.' nalin895 ', NL895) in increasing the yield of wood and a method of the transmembrane protein gene (TRANSMEMBRANE, TRM) for knocking out Popus deltoids * P.eurameracana cv.' nalin895', NL895) in increasing the yield of wood. The method comprises the following steps: obtaining a trm knockout transgenic plant by adopting a CRISPR / Cas9 editing technology; the number of xylem layers in the knocked-out plant is obviously increased, and the number of formed layers is also obviously increased; the result shows that the activity of the stem cambium of the poplar and the xylem differentiation are promoted after the TRM is deleted, and the method has important significance on development and utilization of the poplar.

The present invention discloses an anti-wrinkle skin care solution and its freeze-dried product and preparation method, comprising the following steps: S1, pretreatment of ginseng roots; S2, preparation of ginseng tissue; S3, induction culture: in an induction culture medium, the ginseng tissue obtained in step S2 is induced and cultured to prepare an initial ginseng cambium meristem cell line; S4, suspension culture: the initial ginseng cambium meristem cell line prepared in step S3 is suspended and cultured on a suspension culture medium, filtered through a 40 μm cell sieve, and the filtrate is collected to obtain the anti-wrinkle skin care solution. The anti-wrinkle skin care solution is freeze-dried to obtain an anti-wrinkle skin care freeze-dried product; the present invention uses cell culture fluid cultured with ginseng cells for freeze-drying, which can be applied to skin anti-wrinkle and anti-aging, and has a promoting effect on human cell activity and collagen expression. The method has mild and simple process conditions, no special requirements for equipment, and improves resource utilization, which is conducive to large-scale industrial production.

The invention discloses a wild jujube grafting culture method. The method comprises the following steps: preparing a stock, preparing a wild jujube seedling, preparing an indolebutyric acid solution, picking a scion seed tree and the like. According to the wild jujube grafting culture method, the rootstock is subjected to root cutting, pruning and annular peeling treatment, so that new root germination and nutrient accumulation of the rootstock can be promoted, and the growth vigor of the rootstock and the adaptability of the rootstock to grafting are improved; the scions are soaked in an indolebutyric acid solution, rooting of the scions can be promoted, and the survival rate of the scions is increased; grafting is carried out strictly according to operation requirements in a cleft grafting mode, it is guaranteed that scions and stock cambium layers are well attached, and healing of grafted parts is facilitated; by means of shading treatment after grafting, reasonable water and fertilizer management, timely sprout removal and unbinding and effective pest control measures, good environmental conditions are created for growth of grafted seedlings, so that the survival rate of wild jujube grafting is remarkably increased, and the cultivated wild jujube seedlings grow robustly, are excellent in quality and high in yield and have good economic benefits and social benefits.

The invention belongs to the technical field of biotechnology and plant tissue culture, and particularly relates to a method for promoting ginsenoside accumulation in ginseng cambium stem cells. According to the method for promoting ginsenoside accumulation in the ginseng cambium stem cells, efficient induction and accumulation of ginsenoside in the ginseng cambium stem cells are promoted by optimizing culture conditions and induction strategies. The ginseng cambium stem cells obtained by the method have high ginsenoside content, and especially saponin components such as Ro, Re, Rg2, Rh1 and the like are remarkably improved.

This application relates to a peony grafting wrapping device and method. The peony grafting wrapping device is used to form a peony grafting incision, which includes a first incision and a second incision. The first incision is formed on the rootstock, and the second incision is formed on the scion. The rootstock has a first end face facing the scion. The first incision has a first longitudinal section, which forms a first angle with the first end face. The scion has a second end face facing the rootstock. The second incision has a second longitudinal section, which forms a second angle with the second end face. The first and second angles are equal. The first and second longitudinal sections are in close contact. Using the peony grafting incision of this application for peony grafting can ensure the alignment range of the cambium layers of the scion and rootstock, improving the survival rate of peony grafting.

The invention discloses a big tree bionic supporting and protecting device which comprises two symmetrically-arranged supporting bases, supporting blocks are arranged at the tops of the ends, close to each other, of the supporting bases, and arc-shaped grooves are formed in the ends, close to each other, of the supporting blocks; the device further comprises a bionic supporting device and a supporting bottom rod installed on the supporting block through a bolt, a supporting rod is movably connected to the supporting bottom rod, the outer side wall of the supporting rod is connected with a movable supporting rod through a supporting assembly, and the bottom end of the movable supporting rod is movably connected to the side wall of the supporting bottom rod. The bionic structure has the advantages that the D printing lignin composite material in the arc-shaped groove adopts a gradient density design, and the surface degradation rate is matched with the tree cambium growth rate; a pre-etched tree-shaped degradation path guides the new bark to heal along a specific form, and annular tightening marks of a traditional stent are avoided; the friction coefficient of the contact surface is increased through honeycomb-shaped textures, and meanwhile micro-airflow channels are formed to reduce the humidity of the barks.

The present invention discloses a method for improving the traits of poplar trees. By using the CRISPR / Cas9 system, the GLR3.3a gene and the GLR3.3b gene of poplar trees are knocked out to obtain gene-edited poplar trees. Compared with the wild type, a gelatinous layer appears in the stem cell wall of the gene-edited poplar trees, the widths of the xylem, cambium and cortex in the stem increase, and the cellulose content is significantly increased, endowing the wood with higher strength and tensile strength and improving the mechanical properties of poplar trees.

The application discloses a kind of nothocinnamomum officinale grafting seedling raising methods, belong to the technical field of pepper grafting seedling, the method includes the following steps: (1) top pot pepper stock seedling cultivation: select 2-year-old disease-resistant, drought-resistant, well-growing top pot pepper big green pepper variety seedling as stock;(2) nothocinnamomum officinale scion collection: select current year nothocinnamomum officinale branch as scion, top of pruned scion, compound leaf, get grafting scion;(3) grafting: on the same stock, complete first branch grafting in late December-2 late, complete second bud grafting in late May-early July;(5) management after grafting: grafting survival carries out fertilization and weeding, solve the problem of low grafting survival rate caused by that cambium does not completely adhere when grafting.

The invention belongs to the technical field of ecological monitoring and forest management, and discloses a tree photosynthetic yield and radial growth dynamic response monitoring and time-delay analysis method which comprises the following steps: performing high-resolution dynamic monitoring on radial growth of a sample tree through a micro-tree core technology, collecting a micro-tree core sample, and determining dynamic change of cambium cells; constructing a photosynthetic productivity model, and calculating the daily photosynthetic yield; carrying out normalization processing on radial growth and photosynthetic yield data, fitting a dynamic relationship between the radial growth and the photosynthetic yield by utilizing linear and nonlinear equations, and analyzing and discussing the instantaneity or hysteresis influence of the photosynthetic yield on the radial growth in combination with a time sequence; and judging the response relationship between the photosynthetic yield and the radial growth by adjusting the correlation parameters and the dynamic change trend of the fitting model. According to the method, the research precision and efficiency are remarkably improved, and an important technical support is provided for dynamic research and management of a forest ecosystem.

The present application provides a water-soluble plant wound healing agent and a preparation method. The preparation raw materials of the healing agent include water, water-soluble lanolin, mussel mucopolysaccharide, sodium naphthaleneacetate, willow fresh branch extract and copper sulfate. The healing agent can form a thin film with strong water retention and air permeability when sprayed on the wound of the tree body, preventing water evaporation in the wound xylem, inducing the cambium cells to split faster and promoting the rapid growth of the cambium. Meanwhile, the healing agent can prevent external bacteria from entering the wound of the tree body, achieving the effects of bacteriostasis and sterilization, and avoiding secondary damage caused by pathogenic bacteria infection. After the wound is recovered, the water-soluble lanolin disappears due to volatilization and rainwater flushing, avoiding the burn caused by the invasion of oily substances into the bark. The healing agent has good liquid flowability, film-forming property and water retention, and the raw materials are simple and easy to obtain. The preparation process is simple, and the healing agent can be used to heal the wound under complex conditions such as high position, large area and large quantity by means of a spray pot, a small sprayer and the like, greatly improving the work efficiency.

The invention discloses intelligent seedling raising equipment and method based on red maple cutting seedling raising, and relates to the technical field of seedling raising, the intelligent seedling raising equipment comprises a culture bed, the culture bed is internally provided with a plurality of placing pits, the intelligent seedling raising equipment further comprises a moving block, the moving block is arranged at the top of the culture bed, and a moving device is arranged on the outer side of the culture bed and used for driving the moving block to move; a fixed supporting plate is fixedly connected to the bottom of the moving block, a rotating plate is arranged at the bottom of the fixed supporting plate, soil in the containing pit is inserted through an inserting mechanism at the bottom of one end of the rotating plate, the hole diameter is adjusted through an adjusting assembly according to the size of red maple branches, and then the rotating plate is driven to rotate through a rotating motor; the red maple branches in the placing frame are inserted into the holes through the cutting assembly, automatic cutting is achieved, the pre-drilled holes can prevent branch epidermis and cambiums from being scratched by soil particles during insertion, meristematic cell activity is protected, and the rooting rate is increased.

The invention relates to a large-trunk-diameter fruit tree bark grafting method for sealing and fixing by using polystyrene foam, which comprises the following steps: wrapping a thin plastic film on the cross section of a trunk of a stock to effectively isolate external air and moisture, prevent invasion of germs and reduce water loss; the plastic film can effectively prevent polystyrene foam in later construction from invading a grafting interface, and the problem that interface healing is blocked due to pollution is solved. After the scion is inserted through the marked grafting point, the grafting position of the scion and the stock is fixed through polystyrene foam, a stable protection layer is formed after the polystyrene foam is cured, the joint healing quality is effectively improved, and meanwhile the scion fixing strength is enhanced. The protective layer has good heat preservation and moisture preservation performance, and cambium cell division and healing tissue generation are promoted. After the polystyrene foam is completely cured, the outside is wound and wrapped by a shading film, so that ultraviolet degradation is avoided, and water evaporation is reduced. The whole grafting structure is stable, resistant to wind and rain erosion and suitable for efficient standardized operation of large-scale orchards, and the technical threshold and the labor cost are remarkably reduced.

The application discloses a method and device for grafting artemisia annua to improve yield and quality of chrysanthemum morifolium, and belongs to the technical field of grafting, comprising the following steps: step 1: selecting materials, selecting healthy chrysanthemum morifolium scion as stock, and selecting artemisia annua as rootstock; the rootstock requires thick and strong roots, is free of diseases and pests, and is located on a flat ground with sufficient sunlight and no other obstructions, so as to facilitate subsequent growth and development; step 2: cutting the stock and disinfecting, using a grafting device to cut a grafting incision at the end of the chrysanthemum morifolium scion; the incision requires that the cortex is cut off, and the cambium layer is visible; when the grafting device cannot form at one time, a blade is adjusted, and the length of the cutting is 2-3 cm; the method and device for grafting artemisia annua to improve yield and quality of chrysanthemum morifolium are provided, and are used for solving the problems of low yield and quality of chrysanthemum morifolium products, and the problems of difficulty in cutting the incision of the rootstock during grafting, difficulty in healing the incision after grafting, poor growth quality and low quality.

This invention discloses a method for cultivating hardy kiwifruit, comprising the following steps: S1 Cultivating male 'Jinmi Rootstock No. 1' seedlings; S2 Grafting, starting in mid-to-late February, high-position grafting is performed on the 'Jinmi Rootstock No. 1'; First, a grafting method with a grafting diameter of 0.8 cm is used: the scion is 5-7 cm long, each segment retains 2-3 buds, and the lower end is cut into an oblique surface; the rootstock is cut at a diameter of 0.8 cm, then longitudinally cut, with the cut size similar to that of the scion; then the cambium layers of the scion and rootstock are aligned and tied tightly with a thin film strip. Beneficial effects: 'Jinmi Rootstock No. 1' can increase the average yield of hardy kiwifruit cultivars by 25.7%, showing a significant yield increase; 'Jinmi Rootstock No. 1' has a very well-developed root system, strong vitality, and can be directly propagated by cuttings, making seedling cultivation easy; it improves the adaptability of hardy kiwifruit cultivation and reduces the rate of tree death caused by waterlogging.

The invention belongs to the technical field of grafting equipment, and particularly relates to agricultural seedling grafting equipment which comprises a scabbard, a holding rod fixed outside the scabbard, a rubber pad arranged on the holding rod, a knife rest rotatably connected in the scabbard, a first blade fixedly connected below the knife rest, and a second blade rotatably connected below the knife rest. The cutting edges of the second blade and the first blade are located on the same straight line, the second blade is located at the front end of the bottom face of the knife rest, a sliding groove is formed in the sheath in a penetrating mode, a sliding block and a sliding frame are slidably connected into the sliding groove, a mounting plate is fixed to the tail end of the sheath, and a skin picking device is arranged between the mounting plate and the sliding block and used for driving the second blade to rotate to pick the skin of the branches open. The sliding rod drives the sliding block to move in the sliding groove, then the bark picking device is driven to move, the second blade rotates, the cambium at the end of the notch is picked open, the cambium is separated from the xylem of the branch, then a second notch is formed in the same mode, and the cambium is picked open and separated from the xylem.

The invention discloses application of a poplar PdPXC1 gene in regulating poplar growth, xylem development and cell wall component synthesis. A nucleotide sequence of a coding region of the PdPXC1 gene is shown as SEQ ID NO: 1, and an amino acid sequence coded by the PdPXC1 gene is shown as SEQ ID NO: 3. A PdPXC1 over-expressed or gene-edited transgenic poplar plant can be obtained by constructing a recombinant expression vector containing the gene or a CRISPR / Cas9 gene editing vector and transforming the poplar. Compared with a wild type, the plant height, the ground diameter, the cambium cell number, the xylem width, the cellulose content, the lignin content and the fiber cell wall thickness of the overexpressed plant are all remarkably increased; and the gene editing plant shows an opposite phenotype. The invention provides an important gene target and a breeding material for directionally improving the growth speed of the poplar and the wood quality through a genetic engineering means, and has a wide application prospect in forestry production.

The application provides a high water-retention insoluble fiber and a preparation method and application thereof. The high water-retention insoluble fiber used in the application is derived from wood and wood chip processing by-products, and is obtained through a technical process of removing bark and cambium, cutting, crushing, high-temperature vaporization, pickling and drying, has a water-retention of 634-789%, an insoluble fiber component content of 84.32-88.24%, and a soluble fiber component content of 1.23-1.62%, and can be added into the feed of pregnant sows as a functional fiber raw material, so as to improve the constipation and empty chewing ratio of the pregnant sows, increase the number of live piglets and weaning litter weight of the sows and the mating rate in the next reproduction cycle, reduce the empty chewing ratio in the late pregnancy (100-102d) of the sows and the elimination rate in the next reproduction cycle, and has a wide application prospect in the daily feed of the pregnant sows.

The invention discloses a method for improving the salt tolerance of a woody plant through interspecific grafting, in particular to a method for improving the salt tolerance of a scion through grafting by taking a salt-tolerant variety as a stock, and relates to the field of grafting planting. The method comprises the following steps: (1) cutting an annual branch of a salt-tolerant woody plant as a stock, and cutting a phloem at the upper end and the middle part of a cambium from top to bottom; (2) cutting an annual branch of the woody plant and reserving 2-3 buds as scions; (3) aligning and abutting cambiums on the two sides of the long cutting surface of the scion and cambiums on the two sides of the cut of the stock, and binding with a plastic film strip; after the grafting succeeds, one vigorous leaf bud is reserved in the scion. According to the method, the populus nigra scion is grafted to the salt-tolerant American black poplar stock, so that the salt tolerance of the populus nigra scion is improved, the obtained grafted seedling has better growth advantage and salt tolerance, and the method has important application value in increasing the forest yield and cultivating new salt-tolerant varieties.