47 results about "Leaf water" patented technology

The invention belongs to the technical field of agriculture, particularly relates to a cranberry water demand dynamic sensing system and a method thereof, and aims to solve the problems that an existing traditional irrigation method is often based on a fixed time table or simple soil humidity measurement, the actual water demand condition of cranberries cannot be timely and accurately reflected, and insufficient irrigation or excessive irrigation is easily caused. In order to solve the problems that in the prior art, water resources are wasted, and the growth and yield of cranberries are possibly influenced, the invention provides the following scheme: the system comprises a monitoring module, a control module and a display module, wherein the monitoring module comprises stem flow rate, leaf water potential, soil water content at different depths and positions, air temperature and humidity, illumination intensity and wind speed data; according to the cranberry water demand monitoring system, accurate monitoring, real-time evaluation and scientific prediction of the cranberry water demand condition can be achieved, then a reasonable irrigation decision and environment regulation and control are guided, and the irrigation efficiency and the water resource utilization efficiency are improved.

The invention relates to the technical field of agricultural remote sensing and precise irrigation, in particular to a method and equipment for inverting leaf water potential of grapes before dawn based on multispectral remote sensing, and the method comprises the steps: measuring leaf water potential of representative grape plants in each planting test plot before dawn in different growth periods, and collecting canopy multispectral images in the noon period; preprocessing the remote sensing original image data; calculating a vegetation index; on the basis of the model fitting data set and the training feature set, constructing basic prediction models in different growth periods by adopting a unary linear regression algorithm, a multiple linear regression algorithm and a partial least square regression algorithm respectively; determining a PLSR inversion model according to the decision coefficient and the root-mean-square error; and carrying out pre-dawn leaf water potential prediction through the PLSR inversion model. Through the method, high-precision inversion of the water potential of the leaves before dawn based on the noon canopy multispectral data can be realized, and reliable technical support is provided for accurate management of vineyard moisture and intelligent irrigation.

The utility model provides a continuous operating device of a lotus leaf water-removing machine, which relates to the technical field of lotus leaf water-removing machines and comprises a cleaning box and an operating box, three baffles are arranged in the operating box, conveying arches are arranged on the surfaces of the two baffles, heating wires are arranged on the surfaces of the conveying arches far away from the cleaning box, and a conveying belt is arranged in the operating box. The operation box, the material conveying arch, the electric heating wire, the first air blowing assembly and the second air blowing assembly are adopted, the first draught fan is turned on, lotus leaves move on the top of the material conveying arch along with a cyclone, and therefore water obtained after the lotus leaves are air-dried is discharged through the material conveying arch; the air speed of the first fan is reduced, the air-dried lotus leaves are conveyed through the conveying belt, the second fan is turned on, and meanwhile, the moving lotus leaves are subjected to fixation under the action of the electric heating wire, so that the fixation effect of the lotus leaves is improved, fixation of the lotus leaves is conveniently completed through continuous operation, and manpower and material resources are saved.

The application discloses a drying method of hibiscus flowers. The method comprises the following steps: 1) enzyme inactivation and color protection: the hibiscus flowers are sequentially immersed in an acidic citric acid-vitamin C solution and a solution added with corn stem and leaf water extract, so as to efficiently inactivate oxidase and protect color; 2) composite film construction: a hibiscus leaf extract solution is used as a natural film-forming matrix, is compounded with hydroxypropyl methyl cellulose and the like to form a film-forming solution, the hibiscus flowers are immersed and coated, and a supercritical CO2 drying technology is used to form a uniform and porous protective film on the petal surface; and 3) hot air drying: two-stage gradient temperature and humidity control is adopted for final drying. The application can significantly inhibit enzyme browning and non-enzyme browning in the drying process, effectively reduce the loss of functional components such as anthocyanins and flavonoids, solve the problems of petal blackening, brittleness, fragility and the like caused by traditional drying, and the finished product is full in shape, bright in color, and green in the whole process.

The application discloses a kind of passion fruit plant health monitoring methods using spectral analysis, the method is by simultaneously collecting the spectral data of the top of plant new leaf, middle functional leaf and fruit, it is compared with the standard health spectrum model of prestorage, based on the diagnosis of magnesium deficiency of top leaf 530nm reflection peak, the diagnosis of nitrogen deficiency of middle leaf red edge position blue shift, the diagnosis of water deficiency of middle leaf water index rise, specific waveband spectrum distortion early warning disease and fruit spectrum form evaluation quality, realize multi-index comprehensive diagnosis;The application realizes multi-index diagnosis of plant nitrogen, magnesium nutritional status, water stress, potential disease and fruit quality by simultaneously collecting and analyzing the reflection characteristics of the top of passion fruit plant new leaf, middle functional leaf and fruit in specific spectral band, so as to overcome the problem of the prior art relying on single vegetation index or chlorophyll measurement, which leads to the problem of partial diagnosis information.

This invention provides a non-destructive detection method and device for plant leaf moisture based on dual-modal fusion, belonging to the field of plant water detection technology. The method includes: simultaneously acquiring the current dielectric, micro-deformation, and surface temperature parameters of the target plant leaf; after temperature compensation, using calibrated elastic coefficients and micro-deformation parameters to invert the dynamic thickness variation mapping relationship; accordingly, adaptive morphological interference elimination is performed on the dielectric parameters to obtain thickness-normalized dielectric parameters; finally, the above parameters are used as joint features input to a dual-modal fusion model, and the moisture detection results are decoupled and output. This invention decouples water loss and leaf morphological variation from the underlying physical mechanism, effectively eliminating interference and strain response hysteresis caused by changes in sensor electrode spacing, and significantly improving the accuracy and noise resistance of in-situ continuous monitoring of plant moisture across the entire range.

The invention relates to the field of plant biotechnology and molecular biology, in particular to application of a VvECT10 gene in regulation and control of drought resistance of grapes. A strain with overexpressed VvECT10 gene is slow in leaf water loss and light in withering degree under a drought condition, the content of malondialdehyde (MDA) and hydrogen peroxide (H2O2) is remarkably reduced, and the activity of peroxidase (POD) and catalase (CAT) is remarkably improved, which indicates that the overexpression of the VvECT10 gene can enhance the drought resistance of the grape plant and relieve oxidative damage.

The invention discloses a method for reducing the noon break proportion of citrus stomata based on moisture regulation and control, and particularly relates to the technical field of fruit tree physiological regulation and control. The method comprises the following steps: acquiring a citrus leaf stomatal opening time sequence G (t) and a leaf water potential parameter psi (t), and constructing a stomatal activity response model M1; setting a target noon time period, and calculating a pore closing proportion; establishing a moisture regulation response model M2 according to the soil moisture content and the transpiration rate, and predicting psi (t) changes under different irrigation conditions; inputting the psi (t) output by the M2 into the M1, predicting the influence of different moisture regulation and control strategies on the theta m, and selecting an optimal irrigation scheme to control the target irrigation time, water volume and frequency; dynamic iterative optimization is carried out through theta m actual measurement and a model self-learning mechanism, and accurate moisture management and pore behavior regulation and control are achieved; the method has high adaptability, intellectualization and self-evolution ability, the noon stomata closing proportion can be effectively reduced, and the photosynthetic efficiency and the fruit tree yield are improved.

The invention belongs to the technical field of plant leaf hydraulic characteristic determination, and discloses a corn leaf hydraulic conductivity and embolism curve determination system and method, and the system comprises a corn leaf transpiration amount determination device in a stable state; the invention discloses a convenient leaf water potential balance, dehydration and leaf area measuring device and a dew-point water potential instrument, and the measuring system and method are not only suitable for measuring the maximum hydraulic conductance and embolism curve of the leaf in the whole growth period of corn, but also can realize the goal of simultaneously measuring the maximum hydraulic conductance and complete embolism curve of the corn leaf by using only one corn leaf. According to the method, blade mechanical damage caused by heterogeneity of blades at different positions and a pressure chamber method is avoided, and the measured maximum hydraulic conductivity and embolism curve fitting effect is better.

The invention belongs to the technical field of plant planting, and provides a Hainan camellia oleifera high-survival-rate drought-resistant afforestation and biological nutrient solution preparation method. The special nutrient solution for the camellia oleifera comprises the following raw materials in parts by weight: 6-12 parts of a probiotic agent, 8-12 parts of potassium fulvate, 15-20 parts of potassium nitrate, 60-70 parts of a coco coir extract and 95-105 parts of water. Through the synergistic effect of the afforestation method and the special nutrient solution for camellia oleifera, the survival rate and preservation rate of camellia oleifera afforestation are remarkably increased. Wherein the special nutrient solution has high-temperature-resistant, drought-resistant and root-promoting effects, and can effectively promote the growth of roots of camellia oleifera, improve the water-retaining capacity of leaves and increase the content of available phosphorus in soil, thereby enhancing the stress resistance and growth vigor of plants; in the drought period, the leaf wilting degree of the oil-tea camellia adopting the drought-resistant afforestation method is far lower than that of a traditional method, the water content of soil is higher, and stage drought stress can be effectively resisted.

A kind of tea processing preparation process, it is related to tea processing technical field, solve the problem of different water content of tea fresh leaves due to different degree of sucking and biting of small green leafhopper adults and nymphs and different time interval from sucking and biting to picking.The preparation process includes fresh leaf pretreatment, collision green and aroma enhancement, steam + high hot air fixation, spreading, striping, drying, screening and picking, aroma enhancement and packaging.In the fresh leaf pretreatment process, small green leafhopper adults are put in, and small green leafhoppers are attracted to suck and bite fresh leaves by yellow light.In the collision green process, tea fresh leaves are made to jump by vibration to carry out collision green treatment.The present application solves the problem of different degree of fresh leaf water loss due to different degree of sucking and biting of small green leafhopper adults and nymphs and different time interval from sucking and biting to picking by putting small green leafhopper adults and nymphs to concentrate sucking and biting of tea fresh leaves.Meanwhile, the quality of cicada tea is effectively improved by temperature and humidity control, light supplement, collision green and aroma enhancement, steam + high hot air fixation.

The invention discloses a preparation method of a hippophae rhamnoides branch and leaf water extract and application of the hippophae rhamnoides branch and leaf water extract in inhibition of aquatic pathogenic bacteria. The preparation method comprises the following steps: drying and crushing fresh hippophae rhamnoides leaves or hippophae rhamnoides branches; adding water, and carrying out condensation reflux extraction; removing the solvent in the filtrate; and finally, grinding into powder, namely the sea-buckthorn branch and leaf water extract. The method not only makes full use of sea-buckthorn resources, but also has the advantages of safety, simplicity, convenience and low cost, and is easy to popularize on a large scale; the prepared hippophae rhamnoides branch and leaf water extract shows a good inhibition effect on vibrio aquatic pathogenic bacteria and particularly has an obvious inhibition effect on vibrio parahaemolyticus, the MIC of the hippophae rhamnoides branch water extract reaches 6.25 mg / mL, and the MIC of the hippophae rhamnoides leaf water extract reaches 1.56 mg / mL; the invention can be applied to preparation of aquatic pathogenic bacteria resistant drugs or feed additives, provides a powerful means for control and prevention of vibriosis of aquatic animals, and has important practical value in the aspect of guaranteeing the safety of aquaculture.

The invention relates to a crop leaf water potential estimation method based on hyperspectral reflectivity. The crop leaf water potential estimation method comprises the following steps: measuring the spectral reflectivity and leaf water potential of a leaf under a preset wave band; determining a candidate vegetation index based on the spectral reflectance; screening a target vegetation index from the candidate vegetation indexes based on the relationship between the candidate vegetation indexes and the leaf water potential; and constructing a target prediction model based on the leaf water potential and the target vegetation index, and predicting the leaf water potential of the leaf based on the target prediction model. According to the method, the leaf water potential measurement efficiency is greatly improved, a feasible technical scheme is provided for crop water and fertilizer deficiency diagnosis, and the method has important scientific significance and practical value for improving automation and intellectualization of water and fertilizer management.

The invention belongs to the technical field of cosmetics, and particularly relates to a spray type skin care emulsion as well as a preparation method and application thereof. The skin care emulsion is prepared from the following components in percentage by mass: 0.5 to 2 percent of meadowfoam seed oil, 0.1 to 1.5 percent of panthenol, 0.01 to 0.15 percent of herba centellae extract, 0.1 to 1 percent of dipotassium glycyrrhizinate, 2.1 to 21.5 percent of humectant, 0.1 to 1 percent of emulsifier, 0.01 to 0.15 percent of chelating agent, 0.11 to 1.6 percent of preservative and the balance of aloe barbadensis leaf water. The meadowfoam seed oil, the panthenol and other components are compounded to prepare the spray type emulsion, the components are matched with one another, so that the atomization effect of spray can be effectively improved by reducing the surface tension of the emulsion, the effect that the spray can cover the skin more widely and finely is ensured, and the active components interact with one another, so that the effect of improving the skin quality is achieved. The soothing and repairing effects of the emulsion can be synergistically enhanced.

The invention relates to the technical field of cosmetics, in particular to a soothing, repairing and moisturizing composition and application thereof, essence and a preparation method thereof. The soothing, repairing and moisturizing composition is prepared from the following components in parts by weight: 5 to 10 parts of myrtle leaf water, 1 to 5 parts of plantago major leaf extract, 0.5 to 1.5 parts of murdannia simplex leaf extract, 0.9 to 3 parts of lactic acid bacteria fermentation product and 0.1 to 2 parts of European larch wood extract. The effect is more comprehensive, more effective and more durable.

The application discloses a method for improving drought resistance and oxidation resistance of poplar by improving physiological indexes of the poplar, and the method is irrigating poplar plants with L-glutamic acid solution to improve the physiological indexes of the poplar, including: increasing the relative water content of leaves; reducing the leaf water loss rate; maintaining the stability of the leaf electrolyte permeability; increasing the endogenous proline content of leaves; reducing the expression amount of endogenous proline dehydrogenase, increasing the expression amount of endogenous pyrroline-5-carboxylic acid reductase, reducing the expression amount of endogenous pyrroline-5-carboxylic acid dehydrogenase, and increasing the expression amount of endogenous pyrroline-5-carboxylic acid synthetase; improving the rehydration capacity of drought stress leaves; increasing the content or activity of endogenous catalase; increasing the content or activity of endogenous peroxidase; and increasing the content or activity of endogenous superoxide dismutase.

The present application provides a kind of regulation method for inducing phalaenopsis flower bud differentiation by day and night temperature difference, belong to plant culture technical field, the present application is by collecting each strain phalaenopsis genome single nucleotide polymorphism marker and historical phenotype data constructs temperature threshold prediction model, formulates differential day and night temperature control scheme and embeds optimal cooling curve planning module;During induction, use stem flow sensor and leaf microclimate probe to collect stem flow rate and leaf water potential in real time;Multi-channel physiological signal is input into day and night rhythm perception temperature control network, and the flower probability prediction value and target control temperature parameter are output in real time by artificial intelligence;With the flower rate and refrigeration energy consumption as double target, the energy-saving flowering game optimization model is constructed, the pareto frontier is solved on the agent surface, and the result is written back to the temperature control scheme;The technical problem that temperature control decision cannot simultaneously perceive plant rhythm physiological state and real-time water stress state, leading to the disconnection of temperature control strategy and actual physiological demand of plant is solved.

The application provides a gene mutant for reducing the leaf water loss rate and an application thereof, and belongs to the technical field of genetic engineering. The NtMYB184 gene mutant for reducing the leaf water loss rate has a mutated NtMYB184 gene sequence, as shown in SEQ ID NO. 2. The application also provides a gene editing vector, a transformant, a kit and a method for constructing the NtMYB184 gene mutant for reducing the leaf water loss rate, and an application of the method. The NtMYB184 gene mutant for reducing the leaf water loss rate provided by the application has a leaf water loss rate of 5.72% when placed for 300 minutes, which is lower than the water loss rate (6.87%) of a control WT, indicating that the leaf water loss rate of the NtMYB184 gene mutant (myb184) is lower than that of the control WT.

The invention relates to a tea leaf foliar fertilizer capable of improving stress resistance of tea trees and a preparation method and an application method of the tea leaf foliar fertilizer. According to a formula of the multifunctional tea leaf foliar fertilizer, through combination of organic components such as silicon and humic acid, the cell wall resistance of the tea trees can be effectively enhanced, and the resistance of the tea trees to drought, low temperature and diseases and pests is improved; decline of tea yield and quality caused by environmental factors is reduced, that is, stress resistance of tea trees is improved, and increase of cell wall resistance also has a certain auxiliary effect on reduction of leaf moisture transpiration. Meanwhile, the abscisic acid and the sugar are used as plant growth regulators, so that leaf stomata opening and closing can be regulated, water transpiration is reduced, the growth limitation of tea trees under the drought condition is reduced, the leaf water transpiration is reduced, and the growth ability of the tea trees under the drought environment and the tea yield are improved; the stress resistance of the tea trees can be synergistically improved while the leaf moisture transpiration is reduced.

The application discloses a kind of coupling deep learning and physical mechanism's leaf water use efficiency estimation method, first, the environmental data and leaf water use efficiency of target area historical monitoring period are acquired;Then, construct the carbon dioxide concentration prediction model inside leaf, the trained carbon dioxide concentration prediction model inside leaf is used to predict carbon dioxide concentration inside leaf, the predicted value of carbon dioxide concentration inside leaf is substituted into formula to calculate leaf water use efficiency, the error between leaf water use efficiency estimation value and measured value is calculated, and the model is optimized by back propagation;Finally, the environmental data of target area monitoring period are acquired, and are input into the trained carbon dioxide concentration prediction model inside leaf, to obtain carbon dioxide concentration inside leaf;Leaf water use efficiency is calculated by carbon dioxide concentration formula inside leaf, and the estimation of leaf water use efficiency is completed.The method improves the estimation accuracy of leaf water use efficiency, and realizes continuous estimation.

The invention relates to the technical field of eye drops, in particular to a plant extract-based eye drop, which is prepared from the following components in parts by weight: 75.00 to 85.00 parts of hamamelis virginiana leaf water, 75.00 to 85.00 parts of 1, 2, 4-trimethyl-1, 3-pentanediol monoisobutyrate, 75.00 to 85.00 parts of 1, 2, 4-trimethyl-1, 3-pentanediol monoisobutyrate, 75.00 The traditional Chinese medicine composition is prepared from the following raw materials in parts by weight: 4.00 to 8.00 parts of 1, 3-propylene glycol, 2.00 to 6.00 parts of rose flower extract, 0.50 to 1.50 parts of nicotinamide, 0.50 to 1.50 parts of beta-glucan, 0.50 to 1.50 parts of lutein, 0.2 to 0.7 part of sodium chloride, 0.10 to 0.30 part of sodium hyaluronate, 0.10 to 0.30 part of allantoin, 0.10 to 0.30 part of dipotassium glycyrrhizinate, 0.10 to 0.20 part of folium artemisiae argyi extract, 0.10 to 0.20 part of grapefruit fruit extract, 0.10 to 0.20 part of semen cassiae torae extract and 2.50 to 7.00 parts of taurine. According to the eye drops based on the plant extracts, the soothing and astringing characteristics of the hamamelis virginiana leaf water are fused, and through the synergistic effect of the folium artemisiae argyi extract, the grapefruit extract and the semen cassiae extract, eye metabolism is further improved, the oxidation resistance of eye tissues is enhanced, and eye health is promoted.

The invention relates to the technical field of herbicides, in particular to a biological herbicide based on schizonepeta leaf water extract and a preparation method and application thereof. The invention discloses and proves that the schizonepeta leaf water extract has a remarkable and concentration-dependent allelopathy inhibition effect on seed germination and seedling growth of major weeds barnyard grass in farmland through systematic biological assay for the first time. The extract simultaneously and obviously inhibits the germination potential (germination speed), germination rate (germination ability), root length and bud length (early planting) of barnyard grass, realizes cooperative blocking of a plurality of key links in the early life stage of weeds, and has more thorough prevention and removal effects. The key concentration range (0.033 g / mL-0. 1 g / mL) and the optimal concentration (0.1 g / mL) of the schizonepeta leaf water extract for generating the remarkable inhibition effect are defined, and an accurate matching basis is provided for product development.

The invention relates to application of a potassium efficient gene DT1 in improvement of drought resistance of corn. It is found that the DT1 gene can significantly improve the drought resistance of corn, by overexpressing the DT1 gene in corn, a corn plant with higher drought resistance is successfully constructed, after drought treatment, the relative water content of leaves of the constructed DT1 overexpressed plant is higher than that of wild type leaves, the water loss rate of in-vitro leaves is reduced, and the drought resistance is significantly enhanced; and a gene resource is provided for cultivating a new variety. Compared with a traditional breeding mode, the drought-resistant breeding method has the advantages that the breeding time is short, the purposiveness is high, the breeding period is remarkably shortened, the breeding efficiency is improved, the drought-resistant breeding method has great application value in crop molecule improvement, and a theoretical basis is provided for clarification of a molecular mechanism of plant drought resistance.

The invention belongs to the field of plant genetic engineering, and relates to application and a method of a GmCRY2a gene or a GmCRY2a protein in regulating and controlling the water loss rate of soybean leaves. According to the invention, two GmCRY2a genes in soybean are knocked out, so that a phenotype with high water loss rate of leaves appears. According to the CRISPR / Cas9 knockout technology constructed by the invention, pure and gmcry2a1a2 mutant soybean plants can be obtained, and compared with control soybeans, the water loss rate of in-vitro leaves is remarkably increased along with the increase of time, so that the method can be applied to screening soybeans suitable for growing in high-temperature and arid regions all year round, and has a huge application prospect.

The invention discloses an aloe barbadensis leaf water composition for removing acnes and application thereof, and the composition is prepared from the following components in percentage by mass: 91 to 97 percent of aloe barbadensis leaf water, 1 to 4 percent of nicotinamide, 1 to 4 percent of arbutin, 0.1 to 0.4 percent of benzalkonium bromide and 0.1 to 0.6 percent of chlorhexidine acetate. The invention also provides a preparation method and application of the composition. The method comprises the following steps: weighing the raw materials in proportion, then mixing the aloe barbadensis leaf water, nicotinamide, arbutin, benzalkonium bromide and chlorhexidine acetate in a container, stirring and dissolving uniformly, sampling and detecting to be qualified, disinfecting and sterilizing, and finally, sealing, packaging and storing the aloe barbadensis leaf water, the nicotinamide, the arbutin, the benzalkonium bromide and the chlorhexidine acetate. The composition is used for preparing skin care products for removing acnes. The aloe barbadensis leaf water composition for removing acnes, prepared by the preparation method disclosed by the invention, adopts acnes-removing components derived from the nature, is safe in acnes removal without hurting the skin, restores the skin to a healthy state while repairing the damaged skin, and inhibits the re-breeding of acnes and bacteria.

The invention relates to the field of crop germplasm resource identification and breeding, in particular to an identification method of a drought-enduring germplasm material of Chinese cabbage. The method comprises the following steps: firstly, preparing to-be-identified Chinese cabbage germplasm materials, performing germination period identification, and measuring the relative root length, the relative seedling height, the germination drought resistance index and the relative vitality index of seeds of each Chinese cabbage germplasm material; then seedling stage identification is carried out, and the relative plant fresh weight, the relative water content decreasing amplitude, the specific leaf weight decreasing amplitude, the damage rate, the in-vitro leaf water loss rate decreasing amplitude, the malondialdehyde content increasing amplitude and the proline content increasing amplitude of plants in the five-leaf stage of each Chinese cabbage germplasm material are measured; the membership function value and the average membership function value of each index are calculated in the germination stage and the seedling stage, and the drought tolerance is divided into five levels according to the average membership function value; and finally, comprehensively identifying. The method solves the problems that in the prior art, drought-tolerant planting is carried out only by optimizing an irrigation technology in the drought tolerance research of Chinese cabbages, and the identification and breeding research on the drought tolerance of varieties are few.

Disclosed herein is a system and methods for leaf detection and extraction. The extracted leaf may be used for leaf water potential analysis. In some embodiments, the method comprises identifying the leaf from a point cloud based on an image, determining a pose of the leaf based on the point cloud, and cutting and storing the leaf based on the pose of the leaf.

The application discloses application of N-acetyl-L-cysteine in improving drought resistance of plants and belongs to the technical field of plant cultivation.The application first proposes application of N-acetyl-L-cysteine (NAC) in improving drought resistance of Brassica napus L.And through experiments, it is proved that compared with a control group, the fresh weight, dry weight, root length and chlorophyll content of the Brassica napus L seedlings that are sprayed with 150 muM of N-acetyl-L-cysteine on leaves are improved, the leaf water loss rate is reduced, and the drought stress tolerance of the Brassica napus L is enhanced.This reflects that the drought stress tolerance of the Brassica napus L treated with N-acetyl-L-cysteine is obviously improved.Further experiments are conducted to obtain an optimal application concentration of 150 muM, so that the N-acetyl-L-cysteine can be optimally used in improving the drought stress tolerance of the Brassica napus L.