Adventitious shoot regeneration of Platanus acerifolia Willd. facilitated by Timentin,an antibiotic for suppression of Agrobacterium tumefaciens in genetic transformation

The effects of Timentin and cefotaxime （Cef） on shoot regeneration of the London plane tree （Platanus acerifolia Willd.） and their use for the suppression ofAgrobacterium tumefaciens in Agrobacterium-mediated genetic transformation were compared. Shoot regeneration was significantly reduced on the media with Cef at concentrations from 100 to 500 mg·L^-1. Timentin showed negative effect on plant regeneration at concentrations of 100 and 500 mg·L^-1; however, 300 mg·L^-1 Timentin was shown to facilitate shoot regeneration significantly and the regeneration frequency increased from 64% （control） to 88%. Effective suppression of A. tumefaciens could be obtained with 500 mg·L^-1 Cef, but plant regeneration was completely inhibited at this level. The A. tumefaciens on infected P. acerifolia leaf tissues was visually undetectable after three subcultures on a medium with 300 mg·L^-1 Timentin. Considering the effect of Cef and Timentin on plant regeneration and suppression of Agrobacteria, Timentin at 300 mg·L^-1 is the preferred application in .4. tumefaciens-mediated transformation ofP acerifolia.

Isolation and Crystal Structure of 3β-acetoxy-20 (29)-lupen-28-aldehyde from the Bark of Platanus Acerifolia Willd

The title compound,3β-acetoxy-20（29）-lupen-28-aldehyde,is a pentacyclic triterpene which was first isolated from the acetyl acetate fraction of Platanus acerifolia Willd bark and characterized by 1 H-NMR and 13 C-NMR.Besides,the crystal of the compound was acquired,and the relative configuration of 3β-acetoxy-20（29）-lupen-28-aldehyde was determined by single-crystal X-ray diffraction analysis for the first time.It crystallizes in the monoclinic system,space group C2 with a=14.428（3）,b=6.6620（13）,c=30.399（6）,β=103.73（3）°,Z=4,C32 H50 O3,M r=482.72,Dc =1.130 g/cm 3,V=2838.5（10）3,μ（MoKa）=0.070 mm-1,F（000）= 1064,the final R=0.0657 and wR=0.1855 for 2839 independent reflections （R int=0.0802）and 1963 observed ones （I〉2（I））.Intramolecular van der waals force contributes to the stability of the structure.

Leaf developmental stability of Platanus acerifolia under urban environmental stress and its implication as an environmental indicator

The developmental stability indices,leaf width based fluctuating asymmetry(FA1),and lateral vein length based directional asymmetry(RDA1)of Platanus acerifolia were studied.All the leaves were sampled from 14 sites that were categorized based on different urban environmental stress levels(UESL)in Shanghai metropolitan,China.Besides,foliar stomatal density and stomatal length were also studied as the subsidiary indices to test the availability of developmental stability indices as the indicator under a stressful environment.Results showed seasonal variation of FA1 and RDA1 existed among the 14 sites,but the data showed significant negative correlation between FA1 and UESL(FA1=0.029−0.0009UESL+0.0003UESL2,r=0.7665,P=0.0014).However,a similar trend was not found between RDA1 and UESL.Furthermore,the significant correlation among FA1 and leaf stomatal length and stomatal density implied they could be used as indicators of urban stress levels on a small scale.It seemed that RDA1 was possibly a normal parameter during leaf development but it was unavailable for use as an indicator of urban stresses.

Application and Verification of Logarithmic LinearCorrelation Model of Element Contents Between Tree Ringsand Soils near the Tree Roots

Nine Platanus acerifolia (Ait.) Willd. trees growing in the Nanjing Children Teacher’s School, Nanjing,China, were selected to determine the contents of 13 chemical elements both in the 1994’s growth rings,C(Z, t), and in the soils near the roots, C’(Z, t), of the trees. The results showed that the relationship between C(Z, t) and C’(Z, t) followed the logarithmic linear correlation model, lgC’(Z, t)=a(Z)+b(Z) ig C (Z, t).Based on this model the chrono-sequences of chemical element contents in the soils were reproduced from those in the tree rings; i.e., the dynamic variations in the chemical element contents of the soils at the sites were traced. In this study the chrono-sequences of the chemical elements including Cd, Ph, Mn, Co and Zn in the soils near the roots of a Platanus acerifolia tree from 1957 to 1994 were established, and the background values of Cd, Pb, Mn, Co and Zn in the soil were calculated by taking the lowest values of the chrono-sequences of the element contents as upper limits of the background values.