 หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Distribution Patterns of Latex Sucrose Content and Concurrent Metabolic Activity at the Trunk Level with Different Tapping Systems and in Latex Production Bark of Hevea bras ผู้เขียน: พิศมัย จันทุมา,  ดร.ศรปราชญ์ ธไนศวรรยางกูร, รองศาสตราจารย์ , ดร.พูนพิภพ เกษมทรัพย์, รองศาสตราจารย์ , Eric Gohet, Phillipe Thaler สื่อสิ่งพิมพ์:pdf AbstractDistribution patterns of latex sucrose content and concurrent metabolic activity at the trunk level with different tapping systems, namely 1/2S d/2 (a half spiral cut alternate daily), 1/2S d/3 ET 2.5%.8/y (a half spiral cut one day in tapping followed by two days of rest, stimulated with ethephon, eight applications per year) and DCA (Double Cut Alternate, 2?1/2S d/4 (t,t), two half spiral cuts, each cut tapped alternate on every four days) were studied. RRIM600 rubber trees were used to map the latex metabolic status from different heights on both panel A and panel B. Latex was collected by puncturing trunks at various positions and was analyzed using Latex Diagnosis technique (LD). The concurrent comparison of latex sucrose and inorganic phosphorus concentrations for every sampling position allowed estimating the size and shape of the actual latex regeneration area. Regular tapping induced latex sucrose depletion in tapped panel bark. This sucrose depletion was enhanced by the use of DCA, as a consequence of increased production and therefore higher latex regeneration metabolism. DCA also induced a huge sucrose sink effect above tapped cut on both panel A and panel B and outside the metabolically active area. |
 |
หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Photosynthetic Capacity and Effect of Drought on Leaf Gas
Exchange in Two Rubber (Hevea brasiliensis) Clones) ผู้เขียน:Krissada Sangsing, Xavier Le Roux, ดร.พูนพิภพ เกษมทรัพย์, รองศาสตราจารย์, ดร.ศรปราชญ์ ธไนศวรรยางกูร, รองศาสตราจารย์, ดร.กุมุท สังขศิลา, รองศาสตราจารย์ , Eric Gohet, Phillipe Thaler สื่อสิ่งพิมพ์:pdf AbstractPhotosynthetic capacity, water-use efficiency and nitrogen-use efficiency were compared between
two different rubber clones, PB 260 and PB 217. Plants were grown in 50 dm3 pots in a greenhouse at
Clermont-Ferrand, France under controlled condition. Net CO2 assimilation rate at 1800 ppm CO2
(A1800) and at 360 ppm CO2 (A360), maximum carboxylation rate (Vcmax), electron transport capacity
(Jmax) and nitrogen-use efficiency (A1800/Na, A360/Na, Vcmax/Na and Jmax/Na) of clone PB 260 were
significantly higher than those of clone PB 217. However, the dark respiration rate (Rd), the ratio of lightsaturated
rate of electron transport and maximum rate of carboxylation (Jmax/Vcmax), leaf mass per area
(Ma), leaf nitrogen content (Nm), leaf nitrogen per area (Na), water use efficiency (WUE), SPAD value
(SPAD) and chlorophyll fluorescence ratio (Fv/Fm) were non- significantly different between these
clones. Effects of drought on leaf gas exchange rates was also studied. Net CO2 assimilation rate (A),
stomatal conductance (gs) and transpiration rate (E) showed a declining curve as a function of increased
water stress. WUE was high under severe stress, due to a more rapid decrease of E than A. At 14 days after
stress, gs and E decreased by 80-85%, while A decreased by 60-70%. Drought also reduced leaf water
potential, which was possitively related to stomatal conductance. These results confirmed the potential
genotypic variability of some photosynthetic traits under non-water-limited condition and stomatal
behavior related with hydraulic properties during water stress in rubber trees. |
 |
|