Dodecyl α‐L‐Rhamnopyranosyl‐(1→2)‐β‐D‐fucopyranoside Derivatives from the Glandular Trichome Exudate of Erodium pelargoniflorum

Chemical investigation of the glandular trichome exudate of Erodium pelargoniflorum (Geraniaceae) led to the isolation of two dodecyl disaccharide derivatives, named pelargoside A1 and pelargoside B1 ( 1 and 2 , resp.). The structures of 1 and 2 were determined as dodecyl 4‐O‐acetyl‐α‐L ‐rhamnopyranosyl‐(1→2)‐4‐O‐acetyl‐β‐D ‐fucopyranoside and dodecyl 3,4‐di‐O‐acetyl‐α‐L ‐rhamnopyranosyl‐(1→2)‐4‐O‐acetyl‐β‐D ‐fucopyranoside, respectively, by spectroscopic studies, including 2D‐NMR, and chemical transformations. In addition, undecyl, tridecyl, and tetradecyl homologs of 1 and 2 , named pelargosides A2–A4 and pelargosides B2–B4, were also characterized as minor constituents of the exudate.     

Competition for S and N by associations of three annual range species in lysimeters

Summary Competition for S and N was studied on free draining lysimeters seeded to associations of three annual forages on Josephine loam (Typic Haploxerults), an important soil for revegetation to rangeland production. Forage yields increased and the botanical composition shifted toward subclover (Trifolium subterraneum L.) with added S. Sulfate uptake and plant S concentration were increased as a function of the S applied. Forage yields were related to plant S concentration and N:S ratios. Subclover and filaree (Erodium botrys (Cav.) Bertol.) obtained a larger proportion of their S from fertilizer-S than did soft chess (Bromus mollis L.). Total S uptake was largely from the applied fertilizer, 39% at the intermediate S level and 78% at high S. The replacement series design of the experiment and the use of labeled S and N permitted calculation of competition coefficients for fertilizer S, total S, soil N, and total N uptake for the species in pairwise associations. Sulfur was the factor limiting to subclover where S was not applied, and N was the limiting factor to soft chess and filaree in mixtures with subclover at high S where subclover was able to fix most of its own N. In the mixture of soft chess and filaree competition for S and N was about equally intense for both nutrients at all S levels, and filaree was dominant consistently. Comparison of two methods for estimating the fate of fertilizer S showed that differences in sulfur uptake and leachate losses over the controls provided significantly higher values for sulfur recovery than estimates based on the fate of³⁵S. Contribution of the University of California Hopland Field Station and Dept. of Agronomy and Range Science, Univ. of California, Davis, CA 95616.     

HPLC法测定3种老鹳草药材中没食子酸和柯里拉京的含量

目的：建立老鹳草、野老鹳草、牻牛儿苗中没食子酸、柯里拉京含量测定方法.方法：采用HPLC法,色谱条件：色谱柱为Diamonsil C18 （2）色谱柱（150 mm×4.6 mm,5μm）;流动相为乙腈-0.1％磷酸梯度洗脱;流速为1.0 mL/min;检测波长为274 nm;柱温为25℃.结果：没食子酸和柯里拉京的线性范围分别是：0.2024μg～2.024 0 μg（r =0.999 6）、0.126 0 ～2.520 0μg（r =0.999 2）,平均回收率分别是97.4％（RSD=1.4％）、96.7％（RSD=0.9％）.结论：本法简便、准确、重复性好,可用于老鹳草药材的质量评价.