Effects of uniconazole with or without micronutrient on the lignin biosynthesis,lodging resistance,and winter wheat production in semiarid regions

Lodging stress results in grain yield and quality reduction in wheat. Uniconazole, a potential plant growth regulator significantly enhances lignin biosynthesis and thus provides mechanical strength to plants in order to cope with lodging stress. A field study was conducted during the 2015–2016 and 2016–2017 growing seasons, to investigate the effects of uniconazole sole application or with micronutrient on the lignin biosynthesis, lodging resistance, and production of winter wheat. In the first experiment, uniconazole at concentrations of 0(CK), 15(US1), 30(US2), and 45(US3) mg L^-1 was applied as sole seed soaking, while in the second experiment with manganese(Mn) at concentration of 0.06 g L^-1 Mn, 0.06 g L^-1 Mn+ 15 mg L^-1 uniconazole(UMS1), 0.06 g L^-1 Mn+30 mg L^-1 uniconazole(UMS2), and 0.06 g L^-1 Mn+45 mg L^-1 uniconazole(UMS3), respectively. Uniconazole sole application or with micronutrient significantly increased the lignin content by improving the lignin-related enzyme activities of phenylalanine ammonia-lyase, cinnamyl alcohol dehydrogenase, tyrosine ammonialyase, and peroxidase, ameliorating basal internode characteristics, and breaking strength. The spike length, spike diameter, spikes/plant, weight/spike, yield/spike, and grain yield increased and then decreased with uniconazole application at a higher concentration, where their maximum values were recorded with UMS2 and US2 treatments. The lignin accumulation was positively correlated with lignin-related enzyme activities and breaking strength while, negatively correlated with lodging rate. Uniconazole significantly improved the lignin biosynthesis, lodging resistance, and grain yield of winter wheat and the treatments which showed the greatest effects were uniconazole seed soaking with micronutrient at a concentration of 30 mg L^-1 and 0.06 g L^-1 , and uniconazole sole seed soaking at a concentration of 30 mg L^-1 .

Effects of Uniconazole on Nitrogen Metabolism and Grain Protein Content of Rice

The effects of uniconazole by soaking seeds and spraying leaves at booting stage with different concentrations （0, 20 and 40 mg/kg） on the nitrogen metabolism of flag leaf and grains after flowering, and rice grain protein content and yield were studied with hybrid rice combination Shanyou 63. Under uniconazole treatment, the soluble protein content in flag leaf was increased in early and middle period of grain filling, but this content was nearly the same as or even lower than that of control at maturity; Glutamine synthetase activity in superior and inferior grains and non-protein nitrogen content in superior grains at early stage of grain development were promoted, and moreover, the transforming speed from non-protein nitrogen to protein nitrogen was accelerated; Non-protein nitrogen content was lower than that of control at maturity, but protein nitrogen content at each stage was higher than those of control; Protein nitrogen content in superior and inferior grains and protein nitrogen absolutely accumulative content in a grain both were enhanced and protein content and yield in rice grain were raised. The application of uniconazole by soaking seeds and spraying leaves raised crude protein content by an average of 7.2% and 8.3%, and protein yield by an average of 13.1% and 13.4%, respectively.

Effects of uniconazole rate on agronomic traits and physiological indexes of rapeseed blanket seedling

Mechanized transplanting of rapeseed(Brassica napus L.)blanket seedling is an innovative cultivation technology.Cultivating high quality blanket seedling to ensure high survival rate of seedling after transplanting is the key of the technology.The effects of different uniconazole rates of 0,0.5,1.0,1.5 and 2.0 mg/tray,spraying at one leaf and one heart stage,on selected agronomic traits,physiological indexes and survival rate of two rapeseed cultivars(‘Qinyou 100 and’Yangyou 90)were investigated in 2018 and 2019.Our results showed that the plant height decreased significantly with the increase of uniconazole rate.However,the collar diameter increased significantly with the increase of uniconazole rate up to 1.5 mg/tray,and the leaf area,dry weights of root and shoot increased with increased uniconazole rate up to 1.0 mg/tray.The root to shoot ratios,N concentrations of root and shoot with the uniconazole rates of 1.0 and 1.5 mg/tray were higher than those with other treatments.As uniconazole rate increasing,gibberellin(GA)and auxin(IAA)concentrations of root and shoot decreased,while abscisic acid(ABA)concentrations increased,and cytokinin(CTK)concentrations topped at uniconazole rate of 1.0 mg/tray and decreased thereafter.The seedling survival rates with 1.0 and 1.5 mg/tray were greatly higher than those in other treatments.Regression analysis suggested plant survival rate was positively related to CTK concentrations and negatively to GA concentrations of root and shoot.To achieve high survival rate after mechanized transplanting,our study revealed that the uniconazole applied at a rate of 1.0 mg/tray was recommended as the best,followed by 1.5 mg/tray.The findings would help to enhance qualities of rapeseed blanket seedling and to promote popularization of mechanized transplanting of rapeseed production.

Effects of CuSO_4 and Uniconazole on Mature Embryo Culture in Japonica Rice

In order to establish the system of high frequency plant regeneration for japonica rice mature embryos, the effects of different concentrations of CuSO4 and uniconazole on in vitro culture of mature embryos were studied using three rice cultivars of Kongyu 131, Longjing 24, and Dongnong 425 as test materials. The results showed that callus induction and differentiation of japonica rice mature embryos were apparently improved on the medium with 10-15 μmol·L-1 CuSO4 and 0.50-1.00 mg·L-1 uniconazole. Induction and differentiation rates of different genotype rice mature embryos displayed different sensitivities to CuSO4 and uniconazole. For the callus induction frequency of three varieties, the optimal concentration of CuSO4 was 15.0 mol·L-1. When the concentration of CuSO4 was 15 μmol·L-1, the plantlet differentiation rates of Kongyu 131 and Dongnong 425 got to the highest, while the concentration of CuSO4 was 10 μmol·L-1 for Longjing 24. For the callus induction and plantlet differentiation rates of Kongyu 131 and Dongnong 425, the ideal concentration of uniconazole was 0.50 mg·L-1 and for Longjing 24 was 1.00 mg·L-1.

Effects of Uniconazole on Stem and Leaf Growth and Endogenous Hormone Contents of Dahlia ( Dahlia pinnata Cav.)

[Objectives]This study was conducted to investigate the physiological mechanism of the response of Dahlia pinnata to exogenous uniconazole during vegetative growth.[Methods]The effects of different concentrations(20,30,60 and 80 mg/L)of foliar fertilization on stem and leaf growth,chlorophyll and endogenous hormone contents were investigated using dahlia seedlings(cultivar‘Shiwucaiqiu’)cultivated in the open field.[Results]Different concentrations of uniconazole could make dahlia plants dwarf,shorten internodes,increase stem diameter,and deepen leaf color,and the higher the application concentration,the more significant the effects.Compared with the control group,the relative contents of chlorophyll(SPAD value)in various treatment groups increased,the contents of endogenous GA_(3) and IAA decreased,and the contents of ABA increased.Among them,the contents of IAA and ABA also showed a trend of increasing first and then decreasing.[Conclusions]The results indicated that uniconazole could affect the growth of stems and leaves and plant type by regulating photosynthetic pigments and the levels of endogenous hormones in dahlia,and good dwarfing effect and ornamental value could be obtained under the condition of foliar application concentration of 30 mg/L.This study provides a new experimental basis for the cultivation and application of dahlia.

Effects of Uniconazole on Photosynthetic Characteristics of Dahlia pinnata Cav.under Drought Stress

[Objectives]This study was conducted to explore the physiological mechanism of uniconazole in response to drought stress in Dahlia pinnata.[Methods]With potted seedlings of D.pinnata variety‘Danbanhuang’as an experimental material,the effects of different concentrations(10,20,30 and 50 mg/L)of uniconazole on the photosynthetic characteristics of D.pinnata under drought stress and rewatering conditions were discussed.[Results]With the extension of drought time,the chlorophyll SPAD value,net photosynthetic rate,transpiration rate,and stomatal conductance of each treatment group decreased significantly,while the intercellular CO_(2)concentration showed a trend of first decreasing and then increasing;and after pretreatment of uniconazole spraying on leaves,it could alleviate the inhibition of drought stress on the photosynthesis of D.pinnata,and was beneficial to the recovery of photosynthetic capacity of D.pinnata after rewatering,and the effect of leaf application concentration of 30 mg/L was the best.It showed that exogenous uniconazole helps to improve the drought resistance of D.pinnata.[Conclusions]This study provides a new experimental basis for the chemical regulation of stress resistance in D.pinnata and its production and application.