ความคิดเห็นที่ 9
คำถามลุงหนวด ผมว่าน่าสนใจครับเท่าที่ผมพอตอบได้คือ Malic acid
สร้างขึ้นแล้วแสงพอหรือไม่แล้วแต่ชนิดของกล้วยไม้ เท่าที่ผมเคยอ่านเจอคือ พวก Doritaenopsis plantlet ซึ่งเป็นCAM orchid .ใช้แสงต่างๆกันEffects of photosynthetic photon flux densities (PPFDs) on growth, photosynthesis and anatomy of micropropagated Doritaenopsis were studied after 4 months of acclimatization in a greenhouse at 25?C. The plantlets were transferred to three different PPFDs for four months, i.e. 'low light' (175), 'intermediate light (270) and 'high light' (450 ?mol m-2 s-1). For most of the growth parameters measured i.e. leaf length, leaf area, leaf width, fresh weight, dry weight, chlorophyll (Chl) a/b ratio, were greater for the intermediate light levels after 4 months of acclimatization. The only exception was leaf thickness, which was increased more under high light levels. Results showed that the survival of Doritaenopsis plantlets was greatest (90%) in low light and intermediate light (89%) compared with only (73%) at high light. However, at low light levels, pigment concentrations (chlorophyll a, b and total chlorophyll) were higher. Net CO2 assimilation (A), stomatal conductance (g) and transpiration (E) were higher in plantlets grown at high level PPFD than at low after 4 months of acclimatization. Photosynthetic efficiency (Fv/Fm) decreased insignificantly; only at mid day for the high light treatment whereas leaf temperature and stomatal closure increased compared to low light. Scanning electron microscopic (SEM) images of leaves from acclimatized plantlets showed an increase in wax formation for the high light grown plantlets compared to those at low light. Microscopic analysis of acclimatized root sections showed highly developed multiseriate-velamen layers and higher root cell activity; while shoots had larger leaf air spaces than those of in vitro grown plantlets. These results suggest that physiological acclimation occurs at the intermediate PPFD (270 ?mol m-2 s-1) in Doritaenopsis compared to treatment at the high light level.
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จากคุณ :
the_gift  
- [
20 ธ.ค. 50 19:59:46
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