| Cucumber is an annual vine vegetable,and its stem node can germinate adventitious roots,which can be used for propagation by cuttings or drop-buried vines to increase roots.Propagation by cutting has the advantages of cost-effective and keeping the inherited natures of maternal plants.At the middle-late stages of long-season cucumber cultivation under protected facilities,multiple times of vine dropping are necessary to satisfy the growth-space requirement of plants.However,this operation will gradually extend the distance between the roots and the aerial parts that bear fruits of cucumber,which further weaken plant growth and reduce fruit yield and quality.Burring vines with soils can induce adventitious roots on stem nodes of vining vegetables,and thus promote growth.However,there are few reports on the application of IBA in cucumber cuttings and increasing yield by dropping vines and burying soils.Therefore,in this research,to explore the effects of IBA on the growths of cucumber cutting seedlings derived from different parts,cucumber hypocotyls and stem shoots were firstly soaked with different concentrations of IBA and then used for cuttings.Besides,different treatments combined with burying soils were performed together with vine dropping to check the effects of the management of drop-buried vines on cucumber growth,yield and fruit quality.Following listed the main results of this study.(1)The optimal IBA concentration for cucumber hypocotyl and stem shoot cuttings were60 mg/L and 20 mg/L,respectively.Suitable IBA concentration can promote the growth of cucumber cutting plants.When treated IBA with concentration of 60 mg/L,the total root length,volume,and number of adventitious roots derived from hypocotyl cuttings were significantly increased by 59.9%,53.8%,and 32.4%,respectively,than those of controls;root activity was53.0% higher than the control and was also stronger than IBA treatment with other concentrations;in addition,the plant height and stem diameter were also significantly higher and wider than the control which increased by 10.3% and 22.9%,respectively;the contents of soluble sugar,soluble protein and chlorophyll in leaves respectively showed 18.2%,16.6%,and 26.0% increases than those of the control.Similarly,when treated IBA with the concentration of 20 mg/L,the longest root length,root number,total root length,root volume,and root activity of the cutting plants derived from the main stem shoots were significantly higher than those of the control which were increased by 24.1%,11.3%,60.6%,61.0%,and50.6%,respectively,showing the best treatment effect;leaf area of cutting plants was also significantly larger than that of the control,which was increased by 21.56%;the plant height and stem diameter were also higher and wider than those of the control and the IBA treatments with other concentrations;the soluble sugar and soluble protein contents in leaves were respectively increased by 14.3% and 29.3% than those of the control.(2)The cucumber yield and fruit quality was reduced when the dropping vine was treated with once soil burying and carved injury.At the same growth period of among different treatments,the growth rate of the treatment once soil burying and carved injury was lower than those of both the control and other treatments;while the leaf area and the chlorophyll a,chlorophyll b,and carotenoids in leaves were significantly reduced by 7.4%,8.5%,8.8%,and14.1%,respectively,than those of control;the nitrate content in fruit increased by 3.9%,and the soluble sugar was decreased by 10.2% than those of the control;the total cucumber yield was also lower than those of the control and other treatments.Although total harvested fruit number was higher for the treatment once soil burying and carved injury,the ratio of abnormal fruits was increased to 40.1%.Overall,the above results showed that the treatment of once soil burying and carved injury following multiple times of vine dropping will reduce the cucumber fruit quality and yield.(3)The treatment of multiple times of directly soil burying combined with vine dropping can increase the cucumber fruit quality and yield.Plant growth rate under the multiple directly soil burying treatment was higher than those of both the control and other treatments,and the mortality rate of the plants was only 3.9%;plant height,stem diameter,and leaf area were significantly higher than those of the control,which were respectively increased by 5.4%,9.5%,and 14.4%;the chlorophyll content in leaves had none significant difference;the soluble sugar and soluble protein contents in fruits were significantly higher than those of control,which were increased by 5.5% and 14.1%,respectively;the nitrate content was significantly decreased than the control;total cucumber yield was significantly higher than that of the control,which was increased by 16.5%;the total harvested fruit number was also higher than those of the control and other treatments;the rate of abnormal fruit was 34.4%,and the obtained fruits had relatively good commerciality.All these results showed that the treatment of multiple times of directly soil burying combined with vine dropping can promote plant growth and increase cucumber fruit quality and yield.In conclusion,IBA treatment showed promoting and inhibiting effects on the growth of cucumber cutting plants at relatively lower and higher concentrations,respectively.The suitable IBA concentrations for the cuttings of cucumber hypocotyl and stem shoot were 60mg/L and 20 mg/L,respectively.For the long-season cucumber cultivation under protected facilities,multiple times of directly soil burying combined with vine dropping is conducive to plant growth and cucumber fruit quality and yield.The results of this study provide technical supports for cucumber propagation by cutting and suitable vine management of long-season cucumber cultivation under protected facilities. |
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