Cytoplasmic bridge,as a broader cellular connection structure,exists in plants from Vo/vox to higher plants,but has been subjected to less investigation as compared to plasmodesmata.It has been speculated that the str...Cytoplasmic bridge,as a broader cellular connection structure,exists in plants from Vo/vox to higher plants,but has been subjected to less investigation as compared to plasmodesmata.It has been speculated that the structure may be related to the synchronization of cell division and development during the microsporegenesis and spermatogenesis.During spermatogenesis in bryophytes,the spermatogenous cells are divided into several domains within an antheridium,and their divisions are synchronous.However,their cellular connection system has not been investigated systematically.In this study,we undertook an ultrastructural examination of the structure and dynamics of the intercellular connection system during the spermatogenesis in Funaria hygrometrica Hedw.The result revealed that within each individual domain,synchronously dividing spermatogenous cells were connected with each other by numerous cytoplasmic bridges,which were absent in the walls between different domains.The plasmodesmata connected spermatogenous cells with the cells of jacket layer,and also existed between the jacket layer cells,but absent in the walls between the developing spermatogenous cells.At the latestage of the an theridial development,as the cell wall began to degrade,all of the spermatid cells within anantheridium seem connected with each other by the expanded cytoplasmic bridges.The cytoplasmic bridges retained to the late stage of spermatid's differentiation,and finally,the spermatids synchronously differentiated into spermatozoids.The different internal structures,biogenesis mechanisms and distribution between the plasmodesmata and cytoplasmic bridges suggest that they may play distinct roles during the development of antheridia.展开更多
Somatic embryo is widely used in genetic engineering and cell engineering. This paper reviewed the recent research results of somatic embryogenesis in Cucurbitaceae plants. Somatic embryogenesis is controlled by many ...Somatic embryo is widely used in genetic engineering and cell engineering. This paper reviewed the recent research results of somatic embryogenesis in Cucurbitaceae plants. Somatic embryogenesis is controlled by many factors such as genotype, explant type, seedling age, basal culture medium, carbohydrate, nitrogen, growth regulators, additives and illumination et al.. Abnormality, desynchrony and browning are the main problem existing in Cucurbitaceae somatic embryogenesis. Then some ideas on how to obtain high quality somatic embryo are given. At last, we forecast the application of somatic embryo in breeding of Cucurbitaceae plants.展开更多
The expansion of hydroponics in many countries of the world in the last few decades may be ascribed to the ability of soilless growing systems to avoid various problems arising from the use of the soil. Cucumber （Cuc...The expansion of hydroponics in many countries of the world in the last few decades may be ascribed to the ability of soilless growing systems to avoid various problems arising from the use of the soil. Cucumber （Cucurnis sativus L.） and zucchini （Cucurbita pepo L.） plants were grown in closed-soilless culture under unheated-greenhouse conditions at the experimental farm of University of Tuscia, Central Italy to evaluate the effects of four substrates （rockwool, pumice, perlite, and cocofiber） on growth, yield and plant mineral composition. For both cultures, plants grown in cocofiber, perlite and pumice yielded more than those grown in rockwool. The better temperature regime in cocofiber, perlite and pumice was due to the greater thermal inertia compared to rockwool slabs. Thc concentration of N in zucchini and cucumber leaves was significantly higher in cocofiber, perlite and pumice in comparison to the rockwool treatment. The concentration of K was significantly affected by the substrate only for the zucchini squash with the highest value recorded on the organic substrate （cocofiber）, whereas the Ca concentration was significantly influenced by the growing media only for cucumber with the highest value observed on pumice. Finally, the lowest Mg concentration in leaf tissue was observed on plants grown with the rockwool substrate for both zucchini squash and cucumber. We can conclude that cocofiber, perlite and pumice are suitable for zucchini and cucumber production in closed soilless system, whereas the use of rockwool is more suitable for crops grown under heated greenhouse conditions.展开更多
In order to take advantage of the lignocellulosic material in water hyacinth （Eichhornia crassipes）, dehydration pretreatment in the first step and then sodium hydroxide and hydrogen peroxide pretreatment was perfor...In order to take advantage of the lignocellulosic material in water hyacinth （Eichhornia crassipes）, dehydration pretreatment in the first step and then sodium hydroxide and hydrogen peroxide pretreatment was performed. The microorganism used for the fermentation process was Zimomonas mobilis. Batch fermentation experiments were carried out with four tests using 22 factorial design with two levels leadings to evaluate the effect of NaOH concentration, conditioning salts as independent variables and ethanol produced as a dependent variable. The optimum condition with higher amount of glucose hydrolyzed and ethanol was： substrate conditioning cellulases, it was pretreated 10% NaOH, with 92.38% conversion of glucose to ethanol and yield of 0.47 g ethanol per g of glucose and 0.018 g ethanol per g of biomass.展开更多
Water hyacinth is a raw material for long-term sustainable production of cellulosics ethanol. In this study, the acid pretreatment and enzymatic hydrolysis were used to evaluate to produce more sugar, to be fermented ...Water hyacinth is a raw material for long-term sustainable production of cellulosics ethanol. In this study, the acid pretreatment and enzymatic hydrolysis were used to evaluate to produce more sugar, to be fermented to ethanol. Separated hydrolysis and fermentation （SHF） studies were carried out to produce ethanol from water hyacinth leaves. Dilute sulfuric acid pretreatment and enzymatic hydrolysis were conducted to select the optimum pretreatment conditions. The optimum pretreatment conditions included T = 135 ℃, t = 30 min, and sulfuric acid concentration = 0.1 M. The residue was enzymatically hydrolyzed using the mixture of enzymes cellulase, xylanase and pectinase. The maximum enzymatic saccharification of cellulosic material （76.8%） was achieved. SHF by mono-culture of Saccharomyces cerevisiae KM1195 achieved the highest yields of ethanol. Furthermore, ethanol production was accomplished with the co-culture ofS. cerevisiae TISTR5048 and Candida tropicalis TISTR5045 which produced the highest increase in ethanol Yield. In this case, the ethanol concentration of 3.42 （g/L）, percentage of the theoretical ethanol yield of 99.9%, the ethanol yield of 0.27 g/g and the productivity of 0.22 g/L/h were obtained. This suggested that mild acid pretreatment and co-cultureare promising methods to improve enzymatic hydrolysis and ethanol production from water hyacinth.展开更多
文摘Cytoplasmic bridge,as a broader cellular connection structure,exists in plants from Vo/vox to higher plants,but has been subjected to less investigation as compared to plasmodesmata.It has been speculated that the structure may be related to the synchronization of cell division and development during the microsporegenesis and spermatogenesis.During spermatogenesis in bryophytes,the spermatogenous cells are divided into several domains within an antheridium,and their divisions are synchronous.However,their cellular connection system has not been investigated systematically.In this study,we undertook an ultrastructural examination of the structure and dynamics of the intercellular connection system during the spermatogenesis in Funaria hygrometrica Hedw.The result revealed that within each individual domain,synchronously dividing spermatogenous cells were connected with each other by numerous cytoplasmic bridges,which were absent in the walls between different domains.The plasmodesmata connected spermatogenous cells with the cells of jacket layer,and also existed between the jacket layer cells,but absent in the walls between the developing spermatogenous cells.At the latestage of the an theridial development,as the cell wall began to degrade,all of the spermatid cells within anantheridium seem connected with each other by the expanded cytoplasmic bridges.The cytoplasmic bridges retained to the late stage of spermatid's differentiation,and finally,the spermatids synchronously differentiated into spermatozoids.The different internal structures,biogenesis mechanisms and distribution between the plasmodesmata and cytoplasmic bridges suggest that they may play distinct roles during the development of antheridia.
文摘Somatic embryo is widely used in genetic engineering and cell engineering. This paper reviewed the recent research results of somatic embryogenesis in Cucurbitaceae plants. Somatic embryogenesis is controlled by many factors such as genotype, explant type, seedling age, basal culture medium, carbohydrate, nitrogen, growth regulators, additives and illumination et al.. Abnormality, desynchrony and browning are the main problem existing in Cucurbitaceae somatic embryogenesis. Then some ideas on how to obtain high quality somatic embryo are given. At last, we forecast the application of somatic embryo in breeding of Cucurbitaceae plants.
文摘The expansion of hydroponics in many countries of the world in the last few decades may be ascribed to the ability of soilless growing systems to avoid various problems arising from the use of the soil. Cucumber （Cucurnis sativus L.） and zucchini （Cucurbita pepo L.） plants were grown in closed-soilless culture under unheated-greenhouse conditions at the experimental farm of University of Tuscia, Central Italy to evaluate the effects of four substrates （rockwool, pumice, perlite, and cocofiber） on growth, yield and plant mineral composition. For both cultures, plants grown in cocofiber, perlite and pumice yielded more than those grown in rockwool. The better temperature regime in cocofiber, perlite and pumice was due to the greater thermal inertia compared to rockwool slabs. Thc concentration of N in zucchini and cucumber leaves was significantly higher in cocofiber, perlite and pumice in comparison to the rockwool treatment. The concentration of K was significantly affected by the substrate only for the zucchini squash with the highest value recorded on the organic substrate （cocofiber）, whereas the Ca concentration was significantly influenced by the growing media only for cucumber with the highest value observed on pumice. Finally, the lowest Mg concentration in leaf tissue was observed on plants grown with the rockwool substrate for both zucchini squash and cucumber. We can conclude that cocofiber, perlite and pumice are suitable for zucchini and cucumber production in closed soilless system, whereas the use of rockwool is more suitable for crops grown under heated greenhouse conditions.
文摘In order to take advantage of the lignocellulosic material in water hyacinth （Eichhornia crassipes）, dehydration pretreatment in the first step and then sodium hydroxide and hydrogen peroxide pretreatment was performed. The microorganism used for the fermentation process was Zimomonas mobilis. Batch fermentation experiments were carried out with four tests using 22 factorial design with two levels leadings to evaluate the effect of NaOH concentration, conditioning salts as independent variables and ethanol produced as a dependent variable. The optimum condition with higher amount of glucose hydrolyzed and ethanol was： substrate conditioning cellulases, it was pretreated 10% NaOH, with 92.38% conversion of glucose to ethanol and yield of 0.47 g ethanol per g of glucose and 0.018 g ethanol per g of biomass.
文摘Water hyacinth is a raw material for long-term sustainable production of cellulosics ethanol. In this study, the acid pretreatment and enzymatic hydrolysis were used to evaluate to produce more sugar, to be fermented to ethanol. Separated hydrolysis and fermentation （SHF） studies were carried out to produce ethanol from water hyacinth leaves. Dilute sulfuric acid pretreatment and enzymatic hydrolysis were conducted to select the optimum pretreatment conditions. The optimum pretreatment conditions included T = 135 ℃, t = 30 min, and sulfuric acid concentration = 0.1 M. The residue was enzymatically hydrolyzed using the mixture of enzymes cellulase, xylanase and pectinase. The maximum enzymatic saccharification of cellulosic material （76.8%） was achieved. SHF by mono-culture of Saccharomyces cerevisiae KM1195 achieved the highest yields of ethanol. Furthermore, ethanol production was accomplished with the co-culture ofS. cerevisiae TISTR5048 and Candida tropicalis TISTR5045 which produced the highest increase in ethanol Yield. In this case, the ethanol concentration of 3.42 （g/L）, percentage of the theoretical ethanol yield of 99.9%, the ethanol yield of 0.27 g/g and the productivity of 0.22 g/L/h were obtained. This suggested that mild acid pretreatment and co-cultureare promising methods to improve enzymatic hydrolysis and ethanol production from water hyacinth.
