Effects of different treatment conditions on the cutting rooting of the rare rose 'Blue Moon'
The rose is one of the world's four major cut flowers and has long been known as the "queen of flowers," with blooms that are vivid, rich and varied in colour. Among them, the rare rose 'Blue Moon' is a hybrid tea rose bred in Germany in 1963; because its flower colour falls within the blue range, it is also known as "Blue Moon." It is mostly propagated by grafting, but grafting requires a long cycle and can hardly meet market demand, so studying the effects of different factors on the cutting rooting of 'Blue Moon' in order to achieve rapid propagation is of great significance.
Han Wensheng found that the cutting survival rate of climbing roses was 26.7% when no hormone treatment was used, whereas after treating cuttings with different mass concentrations of NAA and IBA the cutting survival rate ranged from 26.3% to 43.3%, all showing varying degrees of improvement, which indicates that treating cuttings with different mass concentrations of NAA and IBA promotes the survival of softwood cuttings of climbing roses. Research by Liu Yunqiang et al. pointed out that for 'Red Berlin' and 'Da Feng Shou,' soaking in 100 mg/kg NAA as a rooting agent for 10 min gave the highest rooting rates, 72.2% and 68.9% respectively. Yan Haixia et al. concluded that when the NAA concentration was 250 mg/L its effect on roses was promotive, with the highest survival rate reaching 83.33%, the greatest average number of roots at 7 to 8, and the highest original leaf retention rate reaching 81.33%; the plants grew vigorously, the root system was short and thick with few fibrous roots, and plant growth was best. Yang Liucheng's study showed that cutting diameter has a great influence on the survival rate of rooting: as cutting diameter increased, the rooting rate, the number of roots per individual cutting and the survival rate of rooted cuttings all increased; there were also differences in rooting results when branches from different positions were used as cuttings and when the degree of lignification differed. Wang Guoliang found that when upper, middle and lower sections of the same flowering branch were taken as cuttings, upper cuttings rooted noticeably earlier than lower cuttings, while the difference in rooting rate was not significant; this may be caused by differences in the degree of lignification and the distribution of endogenous hormones at different positions on the parent branch. In softwood cutting of plants, retaining an appropriate number of leaves on the cutting favours the accumulation of nutrients through photosynthesis, thereby improving rooting results.
There are few reports on research into the length of rose cuttings and the number of leaves retained on the cutting. In view of this, this experiment studied the effects of cutting length, number of leaves retained and the concentration of the plant growth regulator NAA on the cutting rooting of the rare rose 'Blue Moon,' aiming to find the optimal combination. An L9(34) orthogonal experimental design was used to identify which of NAA concentration, number of leaves retained and cutting length had the most significant effect on the cutting rooting of the rare rose 'Blue Moon' and to find the optimal combination, so as to speed up seedling propagation, reduce production costs, and provide technical support, practical experience and a theoretical basis for improving the cutting survival rate and seedling formation rate of roses and for large-scale cutting propagation.
1 Materials and methods
1.1 Experimental materials
The experiment was conducted in 2015 in the laboratory of Hebei Agricultural University. The material was 'Blue Moon,' introduced into China in recent years, and the cuttings were collected at the Sanfenchang experimental site in Baoding City, Hebei Province.
1.2 Experimental methods
1.2.1 Selection of cuttings: vigorous, disease-free current-year branches were selected (post-flowering branches being preferable), with a flat cut at the upper end and a 45° slanted cut at the lower end, the cut being about 1 cm from the bud.
1.2.2 Disinfection of cuttings: before cutting, the cuttings were soaked in 0.5% potassium permanganate solution for 10 min for disinfection.
1.2.3 Seedbed preparation: the experimental substrate was fresh river sand, which was placed into plastic plug trays, watered thoroughly, sprayed and disinfected with 0.5% potassium permanganate solution, then rinsed 3 times with clean water; cutting was carried out when the substrate moisture content was about 70%.
1.2.4 Experimental design: three factors were set, namely the concentration of the plant growth regulator, the number of leaves retained and the length of the cutting, with three levels for each factor (see Table 1). An L9(34) orthogonal experimental design was used, with no chemical treatment as the control (CK); each treatment had 10 cuttings and was repeated 3 times. One day before cutting, the plug trays were placed in a nutrient box, arranged neatly, and the temperature and humidity were adjusted to the level most suitable for growth. One day before cutting, holes were made with a small wooden stick, and the cuttings were inserted and firmed in. The browning rate, number of roots and rooting rate of the cuttings were recorded at 15 and 30 d respectively.
Table 1 Experimental factors and level design
1.2.5 Treatment of cuttings: preparation method for the NAA solution: to prepare 100 mg/L, weigh 100 mg of NAA, dissolve it in a small amount of NaOH, then make up to 1 L; other concentrations follow the same procedure. The selected cuttings were cut into 5, 10 and 15 cm lengths respectively, with 0, 2 and 4 leaves retained, and were treated with the NAA concentrations according to the orthogonal experimental design table.
1.2.6 Management after cutting: the treated cuttings were inserted into plastic plug trays, and after cutting they were watered thoroughly. In the early stage after cutting, watering was mainly by fine mist spraying, and they were not to be kept too wet so as to avoid root and stem cankers on the branches. After callus formation, water irrigation during the root growth period was reduced and ventilation was provided appropriately, otherwise poor aeration would cause the new roots to rot; a 0.1% concentration solution of 5% carbendazim wettable powder was sprayed regularly.
2 Results and analysis
2.1 Effects of different treatments on the rooting rate of cuttings
Through range analysis (see Table 2 and Table 3), the effects of each factor on the cutting rooting of 'Blue Moon' rose were analysed to determine the primary and secondary effects. The order of influence of the 3 factors in the experiment on the rooting rate was NAA concentration > number of leaves retained > cutting length. Analysis of variance (table omitted) showed that an NAA concentration of 150 mg/L reached an extremely significant level of influence on the rooting rate of cuttings, basically consistent with the changes in the significance of the effects of each factor obtained by range analysis [10]. This experiment shows that the NAA concentration is the decisive factor for the rooting rate of softwood cuttings of 'Blue Moon' rose, and the number of leaves retained is its dominant factor. The results of the multiple comparison table analysis show that the cuttings of treatment 5 had the highest rooting rate, with rooting rates at 15 and 30 days both between 40% and 50%, that is, when the NAA concentration was 150 mg/L, the cutting length was 10 cm and 4 leaves were retained, the cutting effect was best.
Table 2 Orthogonal experiment on the 15-day rooting rate of rose cuttings
Continued Table 2:
Table 3 Intuitive analysis of the orthogonal experimental results for the 30-day rooting rate of rose cuttings
2.2 Effects of different treatments on the number of roots of cuttings
Through range analysis and intuitive analysis tables (see Table 3 and Table 4), the effects of each factor on the number of roots of 'Blue Moon' rose cuttings were shown to determine the primary and secondary effects. The order of influence of the 3 factors in the experiment on the average number of roots was NAA concentration > number of leaves retained > cutting length. Analysis of variance (table omitted) showed that the number of roots of cuttings in treatment 5 had a significant difference compared with the control; as NAA concentration, cutting branch length and number of leaves retained increased, the number of roots gradually increased, and when the NAA concentration was 150 mg/L, the cutting branch length was 10 cm and the number of leaves retained was 4, the number of roots reached its highest; when the NAA concentration reached 200 mg/L and the cutting branch length was 15 cm, the number of roots decreased. The multiple comparison table (table omitted) shows that treatment 5 performed best, with an average number of roots reaching 30.33; NAA concentration had an extremely significant effect on the number of roots of rose cuttings, the number of leaves retained had a significant effect on it, while the effect of cutting branch length was the smallest. This may be because the observation period was relatively short and the growth traits of the rooted rose cuttings had not yet been fully expressed.
Table 4 Intuitive analysis of the orthogonal experimental results for the 15-day root number of rose cuttings
Table 5 Intuitive analysis of the orthogonal experimental results for the 30-day root number of rose cuttings
Continued Table 5:
2.3 Effects of different treatments on the callus induction rate of rose cuttings
Callus is a prerequisite for plant rooting; only after callus has formed can the cutting root and the plant survive. Through range analysis, it can be seen from the intuitive analysis tables of the orthogonal experiment (see Table 5 and Table 6) that the order of influence of the 3 factors in the experiment on the callus induction rate was NAA concentration > number of leaves retained > cutting length. The analysis of variance table (table omitted) shows that the number of leaves retained had a significant effect on the callus induction rate of cuttings. From the multiple comparison table (table omitted) it can be seen that as the number of leaves retained increased, the callus induction rate of cuttings increased accordingly, showing an upward trend; at 15 days after cutting, treatment 4 performed relatively well, and at 30 days after cutting, treatment 5 performed relatively well, which indicates that in the later stage, as the number of leaves increased, callus formation could be better promoted.
Table 6 Intuitive analysis of the orthogonal experimental results for the 15-day callus induction rate of rose cuttings
Continued Table 6:
Table 7 Intuitive analysis of the orthogonal experimental results for the 30-day callus induction rate of rose cuttings
2.4 Optimisation screening for softwood cutting
Number of roots, rooting rate and callus induction rate are important indicators for the qualitative and quantitative evaluation of rooting in cutting propagation. Combining the range analysis and analysis of variance of these indicators, the effects on cutting rooting in this experiment were evaluated. The results show that NAA concentration, cutting length and number of leaves retained all had significant effects on the investigated indicators of rooting traits in softwood cutting of 'Blue Moon' rose (table omitted); the optimal level can be selected from among the significant factors. Among the 3 factors, NAA concentration was the dominant factor in the comprehensive rooting indicators of 'Blue Moon' rose cuttings. The best combination in this experiment was treatment 5: A2B2C3, that is, with an NAA concentration of 150 mg/L, a cutting length of 10 cm and 4 leaves retained, the rooting indicators of the cuttings were all the highest, with an average rooting rate of 50%, an average number of roots of 41 and an average callus induction rate of 16.66%.
3 Conclusion and discussion
As a commonly used method of asexual propagation, cutting propagation has the advantages of stable genetic traits, improved flowering and fruiting, a short seedling-raising cycle, a high propagation coefficient, simple technical equipment, large scale and low cost. The experiment shows that cutting is a relatively good method for rapid propagation; treatment with hormones greatly increases the rooting speed and survival rate of rose cuttings, and differences in hormones and their concentrations have a significant effect on rose cutting rooting. The relationship between plant growth regulators and adventitious root formation has been widely reported, and auxin plays a key role in root formation. Su Liping (2006) treated rose cuttings with NAA and IBA at concentrations of 50, 150 and 300 mg/L respectively and found that the rooting rate was highest when the IBA concentration was 150 mg/L, which is consistent with the conclusion of this experiment. There are few reports on research into the length of cuttings and the number of leaves retained on cuttings.
This experiment selected 'Blue Moon,' a new cultivar of modern rose recently introduced into China, as the research subject. The results of this experiment show that when cutting the European rose 'Blue Moon,' selecting treatment 5, that is, a cutting length of 10 cm, 4 leaves retained on the cutting and treatment with NAA at a concentration of 150 mg/L for 30 min, gave the best effect and could achieve a relatively high survival rate for the cuttings. However, this experiment cannot yet rule out the influence of other factors on the cutting survival of the European rose 'Blue Moon.'
Rose cutting propagation is also affected by many factors, such as the cutting substrate and cutting time. This paper only carried out relevant experimental analysis on NAA concentration, cutting branch length and number of leaves retained on cuttings. Considering the factors comprehensively, the setting of the number of leaves retained was relatively imprecise; if the most suitable number of leaves retained is to be found, follow-up experiments are still needed. This paper provides an experimental basis for follow-up experiments.
The above is the experiment compiled by the Huinong Network editor on the effects of different treatment conditions on the cutting rooting of the rare rose 'Blue Moon,' for your reference.
Cutting and rooting techniques for Fraxinus hupehensis
Cutting and rooting techniques for Fraxinus hupehensis
The rarity and preciousness of Fraxinus hupehensis are beyond doubt. In order to improve the survival rate of cutting-propagated Fraxinus hupehensis plants and to prevent the many enthusiasts of Fraxinus hupehensis from suffering losses, Wuhan Lulin Horticulture now compiles the methods for improving the survival rate of Fraxinus hupehensis as follows:
Method 1: Soaking in growth solution. This is commonly used to promote cutting rooting, seed treatment, fruit ripening, storage and preservation, etc. Leaf-bearing Fraxinus hupehensis cuttings can be placed in 5-10 ml/l indolebutyric acid, soaked for 12 to 24 hours, and then inserted directly into the seedbed. A quick-dip method can also be used: after mixing naphthaleneacetic acid and talcum powder evenly at a ratio of 1 g to 1000 g, wet the lower part of the cutting with clean water, then dip it in a little of the powder and insert it into the seedbed.
Method 2: Spraying with growth solution. The growth solution is prepared at the required concentration and sprayed onto the plants, with the droplets required to be fine and uniform and the sprayed parts moistened as the standard. To make the agent adhere easily to the plant surface, a little emulsifier such as washing powder or neutral soap, or a surfactant or other adjuvant, needs to be added to the agent to increase its adhesion. Note: when spraying, try to spray as much as possible onto the growing parts of Fraxinus hupehensis.
Method 3: Smearing with growth solution. The solution is smeared onto a certain part of the plant. When treating with lanolin, the lanolin containing the agent is smeared directly onto the treated part, mostly onto the wound, which helps promote rooting, and it can also be applied to buds. For the propagation of precious, difficult-to-root plants, such as the asexual propagation of Fraxinus hupehensis, the air-layering incision smearing method can be used. The method is to make a girdling cut on the branch to expose the phloem, smear lanolin containing auxin-type agents onto the incision, keep it moist with moss, etc., and wrap the outside with plastic film to prevent water evaporation.
Method 4: Soil irrigation method. The plant growth regulator is prepared into an aqueous solution and poured directly into the soil or mixed with fertiliser, etc., so that the roots of Fraxinus hupehensis can fully absorb it. For potted flowers, the amount of solution needed depends on the size of the plant and the pot; generally a pot with a 9-12 cm diameter needs 200-300 ml. To promote flowering and control the elongation growth of stems and branches, a 0.1% to 0.3% aqueous solution of succinamic acid and chlormequat can be used for irrigation. Because this method is convenient, quick and easy to operate, it is also the most commonly used method for improving the survival rate of cutting-propagated Fraxinus hupehensis plants.
In fact, to further improve the survival rate of cutting-propagated Fraxinus hupehensis plants, it is necessary to select one- to two-year-old branches for cutting. By selecting suitable branches and choosing a suitable method, you will certainly achieve the survival rate you expect.
Effects of different tree-form pruning techniques on the fresh flower yield of Kushui rose
Kushui rose is a natural hybrid of Rosa serrata and the traditional rose of China, and is grown on a large scale in the Kushui area of Yongdeng, Gansu. Because it is the most commonly used precious floral fragrance raw material and can also be made into rose essential oil, etc., it has now become one of the pillar industries for farmers to escape poverty and become prosperous. However, in the process of cultivating Kushui rose, flower farmers have low fresh flower yields due to insufficient tree-form pruning techniques. This article will describe pruning Kushui rose into different tree forms and summarise the changes in branching ability, branch growth and fresh flower yield of the different tree forms after pruning, in order to provide a reference basis for high yield, landscape shaping and increased ornamental value of Kushui rose.
1 Materials and methods
1.1 Overview of the experimental site
The experiment was conducted in the concentrated resettlement new village for poverty alleviation and relocation from mountains down to the plains of Nanyang Mountain, Songshan Town, Tianzhu County, Wuwei City, Gansu Province (N39°27′, E102°42′). This location is in the plain area of the Hexi Corridor of Gansu and is a typical desert-oasis river-well irrigation area. The average altitude is 1 783 m, the average annual temperature is 7.8°C, the frost-free period is 147 d, the sunshine duration is 2 852 h, the annual precipitation is 180-220 mm, the annual evaporation is 1 800-2 000 mm, and the soil type is sandy loam.
1.2 Experimental methods
Five-year-old Kushui rose was selected as the test material, with a planting density of 2 m between plants and 4 m between rows. In mid-December 2014, after leaf fall in winter, the trees were pruned into a spherical form (the outer contour of the canopy pruned into a sphere), a flat-topped form (the top of the canopy pruned horizontally parallel to the ground) and a spindle form (the outer contour of the canopy pruned into a spindle), with the natural form (a naturally growing tree form without any pruning) as the control (CK). For each tree form, 30 plants were pruned as 1 plot, in a randomised block design, repeated 3 times. From May to June 2015, during the flowering and harvesting period, 10 plants were randomly selected from each plot to record the number of flowers per plant and the fresh flower harvesting mass; in mid-December, the number of new branches per plant was recorded, and the length of new branches was measured with a steel tape measure and the basal thickness of new branches with an electronic vernier caliper, while the plumpness of the buds was observed with the naked eye. An intuitive evaluation was also made of the convenience of inter-row management and the aesthetic effect of the landscape for the different tree forms after pruning. Excel 2007 and DPS 16.0 software were used to collate and analyse the data.
2 Results and analysis
2.1 Effects of different pruning tree forms on branch growth
Note: Different lowercase and uppercase letters in the same column in the table indicate reaching the 0.05 and 0.01 significance levels respectively; the same below.
From Table 1 it can be seen that after Kushui rose was pruned into spherical, flat-topped and spindle tree forms, the number of new branches and the thickness of new branches all increased and the length of new branches decreased. The bud plumpness of the spindle form and the control natural form (CK) was thin and weak, while that of the spherical and flat-topped forms was plump. Compared with the control natural form (CK), the number of new branches of the spherical, flat-topped and spindle tree forms increased by 402.40%, 197.63% and 61.46% respectively; the thickness of new branches increased by 43.59%, 27.22% and 16.17% respectively; and the length of new branches decreased by 67.71%, 50.62% and 16.21% respectively. Among the different tree forms, the spherical tree form had the highest number of new branches and thickness of new branches and the lowest length of new branches; compared with the control natural form (CK), the differences all reached an extremely significant level (P<0.01).
2.2 Effects of different pruning tree forms on fresh flower yield
From Table 2 it can be seen that after Kushui rose was pruned into spherical, flat-topped and spindle tree forms, the number of flowers and the fresh flower yield all increased, but the increases differed among the tree forms. Compared with the control natural form (CK), the number of flowers of the spherical, flat-topped and spindle tree forms increased by 398.77%, 180.92% and 44.55% respectively; the fresh flower yield increased by 396.08%, 180.39% and 43.14% respectively. The order of the number of flowers and fresh flower yield of the different tree forms from high to low was spherical > flat-topped > spindle > natural (CK). The spherical tree form had the highest number of flowers and fresh flower yield; compared with the control natural form (CK), the differences all reached an extremely significant level (P<0.01).
2.3 Effects of different pruning tree forms on inter-row management and landscape aesthetic effect
From Table 3 it can be seen that the different tree forms of Kushui rose, namely spherical, flat-topped, spindle and natural, had different effects on the convenience of fertilising, weeding and harvesting, and also different effects on the landscape effect. After Kushui rose was pruned into the spherical form, fertilising, weeding and harvesting were all convenient; after pruning into the flat-topped form, the rows were prone to closing over, with branches around the canopy interlocking, which affected fertilising and weeding, but the tree body was not tall and the flowers were mainly distributed on the flat top plane of the tree, making harvesting convenient; after pruning into the spindle form, the inter-row space was relatively large and fertilising and weeding were convenient, but the tree body was relatively tall and the top flowers were not easy to harvest; the control natural form (CK) had tree bodies of uneven height, with inter-row branches interlocking, making fertilising, weeding and harvesting all inconvenient. After Kushui rose was pruned into spherical, flat-topped and spindle forms, because the tree form appearance was regular and neat and the differences in appearance between tree bodies were relatively small, and the flowering amount increased, the landscape effect was neat and beautiful; whereas the control natural form (CK) had relatively large differences in tree height and crown width and interlocking branches, showing a chaotic landscape effect.
3 Conclusion and discussion
The organs of Kushui rose used for processing and essential oil extraction are mainly the flowers, and processing is required immediately after harvesting. The fresh flower yield directly determines the quantity of processed products and the amount of essential oil extracted, thereby affecting planting benefits. The experimental results show that after Kushui rose was pruned into spherical, flat-topped and spindle forms, the number of new branches increased, the excessive growth of branches was reduced, flower bud differentiation was promoted, the fresh flower yield increased, and the landscape effect was neat and beautiful, improving the ornamental value.
But comparatively speaking, after pruning into the spherical tree form, the fresh flower yield was the highest, management such as fertilising, watering and harvesting was the most convenient, and the landscape effect was the most beautiful. This pruning tree form can be adopted in Kushui rose cultivation to increase the fresh flower yield, raise cultivation benefits and enhance the attractiveness of rural flower-viewing and flower-appreciation tourism, thereby achieving a simultaneous increase in both direct and indirect benefits. Pruning Kushui rose reduced the height and size of the canopy, inhibited the growth of excessive branches, promoted branch branching growth, made the tree form appear neat and compact in appearance, and thus distributed the branches evenly in space, improving the light utilisation rate and leaf photosynthesis and storing abundant organic matter for flower bud differentiation.
Pruning measures are widely used in fruit tree cultivation; through pruning measures, vegetative growth is inhibited and reproductive growth is promoted. Pruning measures are also one of the main artificial landscaping measures in modern garden landscapes; by pruning, trees are shaped into different appearances, bringing a visual sense of beauty and thereby increasing the ornamental value of the trees.
The experiment compiled above by the Huinong Network editor only studied the response of branch growth and flower bud differentiation to pruning after winter pruning of Kushui rose. In order to maintain a certain pruning tree form, summer pruning and autumn pruning of Kushui rose should also be attempted in summer and autumn, and the response results after such pruning still require further research.