1906:
Water Stress On Physiological and Biochemical Traits of Hybrid Liriodendron Clones

Tuesday, July 28, 2009
Illinois/Missouri/Meramec (Millennium Hotel St. Louis)
Qirui Wang , Henan Academy of Forestry, Zhengzhou, China
Wei Fan , Henan Academy of Forestry, Zhengzhou, China
Xiao-Feng Tan , Key Laboratory of Cultivation and Protection for Non-Wood Forest Trees, Ministry of Education, Central South University of Forestry and Technology, Hunan 410004, China
Lin Zhang , The key Lab. of Non-wood Forest Product of Forestry Ministry, Key Laboratory of Cultivation and Protection for Non-Wood Forest Trees, Ministry of Education, Central South University of Forestry and Technology, Changsha,410004, China
Deyi Yuan , Key Laboratory of Cultivation and Protection for Non-Wood Forest Trees, Ministry of Education, Central South University of Forestry and Technology, Changsha,410004, China
Liriodendron chinense and L. tulipifera are popular plants for ornamentals and timber production. To better select and breed new Liriodendron varieties for drought tolerance, water stress of six F1 hybrid clones of L. chinense × L. tulipifera (9911, 9901, 9907, 9906, 9902 and 9904) were conducted with their parents as the control. Potted seedlings at their water holding capacity were placed in plastic house in mid-July and then different gradients of water stress were achieved under natural conditions. Leave samples were taken to determine their water content, chlorophyll content, proline content and photosynthetic characteristics at 24h, 72h, 120h and 168h after completed water saturation. The results showed that significant difference was present in decrease extent of leave water content under water stress between hybrid clones and their parents. The decrease extent in descending order was CKc, 9911, 9906, 9902, 9904, 9901, CKt, 9907. Water stress caused great damage of chlorophyll in leaves of the two parents. The damage extent in all Liriodendron samples was remarkably different, and in descending order was CKc, CKt, 9904, 9906, 9902, 9901, 9907, 9911. Chlorophyll content of different Liriodendron samples within 168h after water stress in descending order was 9911, 9901, 9907, 9906, 9902, 9904, CKt, CKc. Water stress improved the proline content of Liriodendron. The proline content of 9901 increased up to 360.0 mg·g-1·FW which equaled to approximately three times the CKc. Water stress had great effects on photosynthetic characteristics of Liriodendron. With the increasing of water stress, net photosynthetic rate decreased sharply. The net photosynthetic rate of hybrid clones was much higher than that of CKt and CKc. Evaluation on water tolerance of Liriodendron via fuzzy decision method showed that 9901 and 9911 had the strongest water tolerance capacity, followed by 9907, 9906, 9902, CKt, 9904 and CKc in descending order, indicating that the hybrid clones of L. chinense × L. tulipifera generally exhibited remarkable super-parent superiority in resistance to water stress.