Light Four-quark States and New Observations by BES

Four-quark states are discussed within the constituent quark model. Incompleteness of existed studies of four-quark state with QCD sum rule is analyzed. The masses of diquark cluster were determined by QCD sum rules, and light four-quark states masses were obtained in terms of the diquark. The four-quark state possibility of the newly observed near-threshold p\bar p enhancement, X(1835), X(1812) and X(1576) by BES is discussed.Comment: 4pages, no figure, PTPTEX, talk at the Yukawa International Seminar (YKIS2006), "New frontiers in QCD", Kyoto, Japa

Pea leaf ABA response to short-term heat stress at flowering stage

Non-Peer ReviewedThe balance between abscisic acid (ABA) synthesis and catabolism plays an important role in the plant's response towards multiple abiotic stresses including cold, drought and salt stress; however, the connection between ABA homeostasis and plant's heat response is still elusive. We assessed pea leaf ABA biosynthesis and catabolism at different time periods under 38°C among five pea varieties with varying heat tolerance by profiling the concentrations of ABA and its five key ABA catabolites from the four major ABA metabolic pathways via liquid chromatography-multiple reaction monitoring assay. More ABA accumulated in the ABA metabolism pool at high temperature condition compared to normal temperature; the ABA response started immediately after 3 hour. Heat tolerant varieties had a higher ABA synthesis and turnover rate at high temperature, than their respective heat susceptible counterparts. Further we valida ted that pea ABA responsive protein genes (ABR17 & ABR18) did not relate to the ABA induction above-mentioned. Identification of the key gene for the heat-induced ABA response still remains to be done for a better understanding on ABA's role in heat response, as well as the responsive variation between heat tolerant and sensitive varieties. This study aids in understanding the impact of a warming summer on the pea plant in the perspective of hormone regulation, and gives a new direction to perceive the different heat tolerance among Canadian pea varieties