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.

1-DE/MS Analysis of Proteins Related to the Spathe Color Variation in an Anthurium andraeanum Mutant

[Objectives] This study was conducted to explore the color variation mechanism of Anthurium andraeanum spathe at the protein level. [Methods]The differential proteins of wild type and its white mutant were separated and identified by using one-dimensional gel electrophoresis and mass spectrometry( 1-DE/MS). [Results] Compared with leaves and spadices,the 1-DE patterns of two kinds of spathe proteins were significantly different,and two different bands were detected in wild type spathes and mutant spathes respectively. The four significantly differential bands were selected and analyzed by mass spectrometry,and 138,111,70 and 427 proteins were identified respectively. The results of GO functional annotation analysis showed that the molecular functions of the proteins were mainly catalytic activity and binding,and the main biological processes involved were cellular process and metabolic process. Many proteins involved in the synthesis of anthocyanins and flavonoids,sugar metabolism and some resistance proteins were screened,indicating that the spathe color difference of A. andraeanum‘Pink champion'is not only related to anthocyanin anabolism,but also regulated by various metabolic pathways. [Conclusions]The study provides a new experimental basis for elucidating the molecular mechanism of the regulation of A. andraeanum flower color.

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.

Study on the Genetic Transformation Conditions of Begonia wallichiana L.with Leaf Disc Method and Corresponding Identification Techniques

[Objectives]This study was conducted to improve the Agrobacterium-mediated genetic transformation system of Begonia wallichiana.[Methods]With sterilized tube seedling leaves as the recipient material and GFP as the reporter gene,optimization experiments were carried out in terms of infection time and method,co-cultivation time and method,and PCR detection technology.[Results]The transformation effect was better under the conditions of shaking Agrobacterium liquid,infection time of 1-2 h,and co-cultivation on sterilized filter paper for 2 d.After co-cultivation,the recipient material was first subjected to recovery culture,and then used for Hyg gradient screening,which was conducive to obtaining resistant transformants.The designed specific PCR detection technology could quickly identify false positives in resistant regenerated plants,and the proportion of transgenic plants was 16.7%.[Conclusions]The research results provide a new technical reference for the genetic transformation of ornamental plants.