is a pioneer species in mangrove. It can naturally grow in both saltwater and freshwater. The study was aimed at investigating and comparing the anatomical character of the
plants growing in ...different conditions and how they coped with salinity. The anatomical characteristics of roots, stems, petioles and leaf blade were investigated. The plant samples were prepared into permanent slides using a paraffin method, while the wood samples were made into permanent slides using a sliding microtome technique. Tissue clearing of leaf blade and scanning electron microscopic analysis of wood were performed. In addition, sodium chloride content in various organs and tissues was examined. It was found that cable root, stem and leaf blade showed some different anatomical characteristics between the two conditions. Periderm is a prominent tissue in saltwater roots. Tanniferous cells were observed in pneumatophores, petioles, stems and leaf blades of saltwater plants, but not found in pneumatophores and lamina of freshwater plants. Mesophyll thickness was lower in the saltwater condition. The vessel density was significantly higher in the saltwater condition than in the freshwater condition, whereas the vessel diameters in the freshwater condition were significantly higher than those in the saltwater condition. From the results, it can be concluded that root periderm plays an important role in salt exclusion, and the occurrence of tanniferous cells is associated with salt elimination.
Characteristics of the reproductive organs and phenology of Thalassia hemprichii using samples collected from the Andaman Sea, West coat of Thailand, are described. Permanent slides of specimens were ...prepared by the paraffin method. Preparations were observed under a stereo microscope and a light microscope. The occurrences of reproductive organs were recorded monthly for one year. Staminate and carpellate flowers are actinomorphic. They have three tepals and are unscented. Secretory cells were found in tepals, connective parenchyma of the anther and ovary wall. The pollen grains are spherical and 30-50 μm in diameter. Numerous long papillae were found on the stigmas. One to nine viviparous seeds were observed per fruit. The reproductive organs occurred in the greatest number during the lowest tides during the night time and when temperatures were 24 to 26°C (December to March). The reproductive organs tend to change with water depth. They decrease when the water depth increases. The highest number of staminate flowers (168.67±47.05 m^(-2)), carpellate flower (205.67±41.23 m^(-2)) and fruit (161.17±31.16 m^(-2)) were found at 1.5 m above lowest low water (LLW).
Maize (Zea mays L.) yield is greatly affected by the environmental and cultivate pattern. Grain filling and dehydration play important roles in maize grain dry mass accumulation and are important ...biological processes in maize growth and development. Four maize cultivars were planted at Hebei province with planting densities of 60000 and 75000 plants/ha during 2017-18. The kernel fresh weight and dry weight of four cultivars were measured at 15, 22, 29, 36, 43, 50 and 57 days after pollination of two planting densities. Logistic model was used to estimate the grain filling process in different environments. The results showed that the maximum filling rates of all cultivars under two planting densities were attained at about 25 days after pollination. The grain filling period was longer under the planting density of 60000 plants/ha. Meanwhile, the grain dehydration was slower. With the increased of planting density, 100-grain weight of per plant decreased while the yield increased. The higher yield was contributed by the larger numbers of plants. It indicated that suitable higher planting density will enhance the yield of maize. Bract, cob and grain water content were significantly correlated. This study indicated a negative effect of dense planting on grain filling.
Understanding of the response of tropical and temperate maize (Zea mays L.) to drought is the first step for tolerant temperate maize improvement. Eight maize hybrids were used to investigate ...physiology responses under drought stress, four of them were tropical maize and the others were temperate maize. Results showed that there were different drought tolerances but similar trends in both tropical maize and temperate maize. Gas exchange parameters revealed different strategies of maize under the stress. In our study, most of the temperate hybrids maintained open stomata to keep a higher photosynthesis rate at the beginning of stress, while the other hybrids decreased stomatal conductance. Compared to temperate maize, the tropical maize had higher antioxidase activity and greater physiological parameter variation among hybrids. KS5731 and ZD309 had stronger drought resistance among tropical and temperate maize hybrids separately. Tolerant hybrids maintained active photosynthesis, have higher osmotic adjustment ability and antioxidase activities but lower malonaldehyde content than the sensitive ones. Our results led to a better understanding of the physiological responses of tropical and temperate maize plants to drought stress and may provide an insight of breeding for drought resistance in maize.
Sonneratia caseolaris is a pioneer species in mangrove. It can naturally grow in both saltwater and freshwater. The study was aimed at investigating and comparing the anatomical character of the S. ...caseolaris plants growing in different conditions and how they coped with salinity. The anatomical characteristics of roots, stems, petioles and leaf blade were investigated. The plant samples were prepared into permanent slides using a paraffin method, while the wood samples were made into permanent slides using a sliding microtome technique. Tissue clearing of leaf blade and scanning electron microscopic analysis of wood were performed. In addition, sodium chloride content in various organs and tissues was examined. It was found that cable root, stem and leaf blade showed some different anatomical characteristics between the two conditions. Periderm is a prominent tissue in saltwater roots. Tanniferous cells were observed in pneumatophores, petioles, stems and leaf blades of saltwater plants, but not found in pneumatophores and lamina of freshwater plants. Mesophyll thickness was lower in the saltwater condition. The vessel density was significantly higher in the saltwater condition than in the freshwater condition, whereas the vessel diameters in the freshwater condition were significantly higher than those in the saltwater condition. From the results, it can be concluded that root periderm plays an important role in salt exclusion, and the occurrence of tanniferous cells is associated with salt elimination.
To evaluate the potential of algal biotechnology to replace traditional agriculture in northeastern Thailand, an open raceway cultivation system was developed to produce biomass and beta‐carotene. ...Dunaliella salina KU 11 isolated from local saline soil was cultured in open raceway tanks using brine and saline lake water. Grown in modified Johnson's medium (with 2–3.5 M NaCl), the algae reached a maximum cell density on the fourth day (1.8 × 106 cells mL−1). Increasing KNO3 and NaHCO3 from 0.5 and 0.043 g L−1 to 1 and 2.1 g L−1, respectively, significantly improved the yields of biomass (0.33 g L−1) and beta‐carotene (19 mg L−1). Expected profits for algal production were evaluated, and it was found that this strain was suitable for outdoor cultivation and the developing algal industry in northeastern Thailand could produce high economic benefits (at least $64,120 per year per 0.16 ha).
Occurrence of tetraploidy in colchicine-treated physic nut (Jatropha curcas Linn.) Rojrawee Piromya(Kasetsart University, Bangkok (Thailand). Agro-ecological System Research and Development Institute) E-mail:rdgrwp@ku.ac.th; Prasart Kermanee(Kasetsart University, Bangkok (Thailand). Faculty of Science. Department of Botany)
Witthayāsān Kasētsārt. Sākhā thammācht,
Jan-Feb 2013
Journal Article
The anatomy and properties of woods in the genus Spondias (Anacardiaceae) were investigated. Wood samples were collected from North and Northeast Thailand. Permanent slides of wood sections and ...tissue maceration were made. The specimens were observed under a light microscope and using scanning electron microscopy. The wood density, specific gravity and hardness were also investigated. It was found that the wood of all three species had indistinct growth rings and fine textured and straight grain. Kribs heterogeneous rays type I were found in Spondias lakonensis while Kribs heterogeneous rays type III were found in Spondias pinnata and Spondias cytherea. Radial canals were present in rays of all studied species. Prismatic crystals were found in the rays of S. lakonensis and S. cytherea but not in S. pinnata. Starch grains were also observed in S. pinnata and S. cytherea. The wood specific gravity of S. pinnata, S. lakonensis and S. cytherea was 0.45, 0.33 and 0.30; the wood density was 0.44, 0.33 and 0.27 g/cm3 and the wood hardness was 2795.85, 1329.26 and 1059 N, respectively. The results from this study suggest that Spondias woods can be used for agricultural utensils but they are not suitable for heavy construction.
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