Maize is widely planted throughout the world and has the highest yield of all the cereal crops. The arid region of North- west China has become the largest base for seed-maize production, but water shortage is the bot...Maize is widely planted throughout the world and has the highest yield of all the cereal crops. The arid region of North- west China has become the largest base for seed-maize production, but water shortage is the bottleneck for its long-term sustainability. Investigating the transpiration of seed-maize plants will offer valuable information for suitable planting and irrigation strategies in this arid area. In this study, stem flow was measured using a heat balance method under alternate furrow irrigation and double-row ridge planting. Meteorological factors, soil water content （e）, soil temperature （Ts） and leaf area （LA） were also monitored during 2012 and 2013. The diurnal stem flow and seasonal dynamics of maize plants in the zones of south side female parent （SFP）, north side female parent （NFP） and male parent （MP） were investigated. The order of stem flow rate was： SFP〉MP〉NFP. The relationships between stem flow and influential factors during three growth stages at different time scales were analyzed. On an hourly scale, solar radiation （Rs） was the main driving factor of stem flow. The influence of air temperature （Ta） during the maturity stage was significantly higher than in other periods. On a daily scale, Rs was the main driving factor of stem flow during the heading stage. During the filling growth stage, the main driving factor of NFP and MP stem flow was RH and Ts, respectively. However, during the maturity stage, the environ- mental factors had no significant influence on seed-maize stem flow. For different seed-maize plants, the main influential factors were different in each of the three growing seasons. Therefore, we identified them to accurately model the FP and MP stem flow and applied precision irrigation under alternate partial root-zone furrow irrigation to analyze major factors affecting stem flow in different scales.展开更多
Haloxylon ammodendron, with its tolerance of drought, high temperature, and salt alkali conditions, is one of the main sand-fixing plant species in the oasis-desert transition zone in China. This study used the TDP30(...Haloxylon ammodendron, with its tolerance of drought, high temperature, and salt alkali conditions, is one of the main sand-fixing plant species in the oasis-desert transition zone in China. This study used the TDP30(where TDP is the thermal dissipation probe) to measure hourly and daily variations in the stem sap flow velocity of H. ammodendron at three age-classes(10, 15, and 20 years old,which were denoted as H10, H15, and H20, respectively) in the Minqin oasis-desert transition zone,China, from May through October 2020. By simultaneously monitoring temperature, relative humidity,photosynthetically active radiation, wind speed, net radiation, rainfall, and soil moisture in this region, we comprehensively investigated the stem sap flow velocity of different-aged H. ammodendron plants(H10,H15, and H20) and revealed its response to physical factors. The results showed that, on sunny days, the hourly variation curves of the stem sap flow velocity of H. ammodendron plants at the three age-classes were mainly unimodal. In addition, the stem sap flow velocity of H. ammodendron plants decreased significantly from September to October, which also delayed its peak time of hourly variation. On rainy days, the stem sap flow velocity of H. ammodendron plants was multimodal and significantly lower than that on sunny days.Average daily water consumption of H. ammodendron plants at H10, H15, and H20 was 1.98, 2.82, and 1.91kg/d, respectively. Temperature was the key factor affecting the stem sap flow velocity of H. ammodendron at all age-classes. Net radiation was the critical factor influencing the stem sap flow velocity of H.ammodendron at H10 and H15;however, for that at H20, it was vapor pressure deficit. The stem sap flow velocity of H. ammodendron was highly significantly correlated with soil moisture at the soil depths of 50and 100 cm, and the correlation was strengthened with increasing stand age. Altogether, our results revealed the dynamic changes of the stem sap flow velocity in different-aged H. ammodendron forest stands and its response mechanism to local physical factors, which provided a theoretical basis for the construction of new protective forests as well as the restoration and protection of existing ones in this region and other similar arid regions in the world.展开更多
[Objectives]This study was conducted to study the variation laws and characteristics of stem sap flow rate in jujube under the injection irrigation mode,to improve the growth quality of jujube trees.[Methods]According...[Objectives]This study was conducted to study the variation laws and characteristics of stem sap flow rate in jujube under the injection irrigation mode,to improve the growth quality of jujube trees.[Methods]According to the characteristics of the growth environment and physiological characteristics of jujube Junzao trees in southern Xinjiang,eight different injection irrigation modes were designed.Through the variation of stem sap flow rate,the most suitable irrigation method for jujube Junzao trees in southern Xinjiang was explored.The variation law of stem sap flow rate of jujube and the effect of meteorological factors on stem sap flow rate of jujube were studied.The variation law of stem sap flow in jujube trees was analyzed,and multiple regression models and time series models were established to predict stem sap flow of jujube trees.[Results]The results showed that the simulation results of the time series model were closer to the actual data,and the model could accurately predict the stem sap flow rate of Junzao.[Conclusions]This study is suitable for the full utilization of water resources in the Tarim Basin in southern Xinjiang,and has important practical significance for analyzing the effect of water stress on the growth and development of jujube trees and precision irrigation.展开更多
The CO_2 released from respiring cells in woody tissues of trees can contribute to one of three fluxes:efflux to the atmosphere(E_A),internal xylem sap transport flux(F_T),and storage flux(DS).Adding those fluxes toge...The CO_2 released from respiring cells in woody tissues of trees can contribute to one of three fluxes:efflux to the atmosphere(E_A),internal xylem sap transport flux(F_T),and storage flux(DS).Adding those fluxes together provides an estimate of actual stem respiration(R_S).We know that the relative proportion of CO_2 in those fluxes varies greatly among tree species,but we do not yet have a clear understanding of the causes for this variation.One possible explanation is that species differ in stem radial CO_2 conductance(g_c).A high g_c would favor the E_A pathway and a low g_cwould favor the F_Tpathway.However,g_chas only been measured once in situ and only in a single tree species.We measured g_cusing two methods in stems of Fraxinus mandshurica Rupr.(ash)and Betula platyphylla Suk.(birch)trees in situ,along with R_S,E_A,F_T and DS.Stem radial CO_2 conductance was substantially greater in ash trees than in birch trees.Corresponding to that finding,in ash trees over 24 h,E_Aconstituted the entire flux of respired CO_2 ,and F_Twas negative,indicating that additional CO_2 ,probably transported from the root system via the xylem,was also diffusing into the atmosphere.In ash trees,F_T was negative over the entire 24 h,and this study represents the first time that has been reported.The addition of xylem-transported CO_2 to E_A caused E_Ato be 9% higher than the actual R_Sover the diel measurement period.Birch trees,which had lower g_c,also had a more commonly seen pattern,with E_A accounting for about 80% of the CO_2 released from local cell respiration and F_T accounting for the remainder.The inorganic carbon concentration in xylem sap was also lower in ash trees than in birch trees:2.7 versus 5.3 mmol L^(-1),respectively.Our results indicate that stem CO_2 conductance could be a very useful measurement to help explain differences among species in the proportion of respired CO_2 that remains in the xylem or diffuses into the atmosphere.展开更多
We report combination of explants and enzymatic protocol as mixed enzymatic-explant procedure to faster extraction of MSCs from WJ. Umbilical cords (UC) were collected from Imam Khomini Hospital. For explant outgrowth...We report combination of explants and enzymatic protocol as mixed enzymatic-explant procedure to faster extraction of MSCs from WJ. Umbilical cords (UC) were collected from Imam Khomini Hospital. For explant outgrowth, 6 - 9 pieces of WJ were transferred onto tissue culture flask and waited for attachment. For mixed enzymatic-explant, 1 cm3 pieces WJ were placed in enzymatic cocktail comprising 4 mg/ml Collagenase Type I and 1 mg/ml Hyaluronidase and 0.1% trypsin-EDTA. Then isolated cells were analyzed for surface cell markers such as CD73, CD31. Isolated 1.0 × 106 MSCs/ml were encapsulated in alginate hydrogel. Cells with MSCs phenotype were isolated from mixed enzymatic-explant and explant procedures within 24 - 48 hrs and 7 - 10 days, respectively. Both of procedures were shown to form clumps and colonies with dense centers. Phenotypic changes gradually appeared as round cell in UC pieces into homogeneous spindle-shaped and typical fibroblast-like shape cells. By using flow cytometery MSCs showed positive for CD73, and negative for CD31. the morphology of viable MSCs in the beads did not significantly show a different morphology pattern before and after the bead formation process. These findings are indicated that when mixed enzymatic-explant procedure is performed MSCs can be isolated faster and much higher from WJ. These finding is important in comparing with time consuming explants culture for isolation of MSCs.展开更多
基金grants from the National Natural Science Foundation of China (51222905, 51321001, 51439006)the National High-Tech R&D Program of China (863 Program, 2011AA100505)+1 种基金the Ministry of Water Resources of China (201201003)the Program for New Century Excellent Talents in University, Ministry of Education, China (NCET11-0479)
文摘Maize is widely planted throughout the world and has the highest yield of all the cereal crops. The arid region of North- west China has become the largest base for seed-maize production, but water shortage is the bottleneck for its long-term sustainability. Investigating the transpiration of seed-maize plants will offer valuable information for suitable planting and irrigation strategies in this arid area. In this study, stem flow was measured using a heat balance method under alternate furrow irrigation and double-row ridge planting. Meteorological factors, soil water content （e）, soil temperature （Ts） and leaf area （LA） were also monitored during 2012 and 2013. The diurnal stem flow and seasonal dynamics of maize plants in the zones of south side female parent （SFP）, north side female parent （NFP） and male parent （MP） were investigated. The order of stem flow rate was： SFP〉MP〉NFP. The relationships between stem flow and influential factors during three growth stages at different time scales were analyzed. On an hourly scale, solar radiation （Rs） was the main driving factor of stem flow. The influence of air temperature （Ta） during the maturity stage was significantly higher than in other periods. On a daily scale, Rs was the main driving factor of stem flow during the heading stage. During the filling growth stage, the main driving factor of NFP and MP stem flow was RH and Ts, respectively. However, during the maturity stage, the environ- mental factors had no significant influence on seed-maize stem flow. For different seed-maize plants, the main influential factors were different in each of the three growing seasons. Therefore, we identified them to accurately model the FP and MP stem flow and applied precision irrigation under alternate partial root-zone furrow irrigation to analyze major factors affecting stem flow in different scales.
基金supported by the National Natural Science Foundation of China Subsidization Project (32260425, 31860238)the Natural Science Foundation of Gansu Province, China (32060246, 21JR7RA733)。
文摘Haloxylon ammodendron, with its tolerance of drought, high temperature, and salt alkali conditions, is one of the main sand-fixing plant species in the oasis-desert transition zone in China. This study used the TDP30(where TDP is the thermal dissipation probe) to measure hourly and daily variations in the stem sap flow velocity of H. ammodendron at three age-classes(10, 15, and 20 years old,which were denoted as H10, H15, and H20, respectively) in the Minqin oasis-desert transition zone,China, from May through October 2020. By simultaneously monitoring temperature, relative humidity,photosynthetically active radiation, wind speed, net radiation, rainfall, and soil moisture in this region, we comprehensively investigated the stem sap flow velocity of different-aged H. ammodendron plants(H10,H15, and H20) and revealed its response to physical factors. The results showed that, on sunny days, the hourly variation curves of the stem sap flow velocity of H. ammodendron plants at the three age-classes were mainly unimodal. In addition, the stem sap flow velocity of H. ammodendron plants decreased significantly from September to October, which also delayed its peak time of hourly variation. On rainy days, the stem sap flow velocity of H. ammodendron plants was multimodal and significantly lower than that on sunny days.Average daily water consumption of H. ammodendron plants at H10, H15, and H20 was 1.98, 2.82, and 1.91kg/d, respectively. Temperature was the key factor affecting the stem sap flow velocity of H. ammodendron at all age-classes. Net radiation was the critical factor influencing the stem sap flow velocity of H.ammodendron at H10 and H15;however, for that at H20, it was vapor pressure deficit. The stem sap flow velocity of H. ammodendron was highly significantly correlated with soil moisture at the soil depths of 50and 100 cm, and the correlation was strengthened with increasing stand age. Altogether, our results revealed the dynamic changes of the stem sap flow velocity in different-aged H. ammodendron forest stands and its response mechanism to local physical factors, which provided a theoretical basis for the construction of new protective forests as well as the restoration and protection of existing ones in this region and other similar arid regions in the world.
基金Supported by Principal Fund of Tarim University(TDZKQN201708).
文摘[Objectives]This study was conducted to study the variation laws and characteristics of stem sap flow rate in jujube under the injection irrigation mode,to improve the growth quality of jujube trees.[Methods]According to the characteristics of the growth environment and physiological characteristics of jujube Junzao trees in southern Xinjiang,eight different injection irrigation modes were designed.Through the variation of stem sap flow rate,the most suitable irrigation method for jujube Junzao trees in southern Xinjiang was explored.The variation law of stem sap flow rate of jujube and the effect of meteorological factors on stem sap flow rate of jujube were studied.The variation law of stem sap flow in jujube trees was analyzed,and multiple regression models and time series models were established to predict stem sap flow of jujube trees.[Results]The results showed that the simulation results of the time series model were closer to the actual data,and the model could accurately predict the stem sap flow rate of Junzao.[Conclusions]This study is suitable for the full utilization of water resources in the Tarim Basin in southern Xinjiang,and has important practical significance for analyzing the effect of water stress on the growth and development of jujube trees and precision irrigation.
基金supported by the National Natural Science Foundation of China(31670476 and 31100284)the Fundamental Research Funds for the Central Universities(2572016CA02)
文摘The CO_2 released from respiring cells in woody tissues of trees can contribute to one of three fluxes:efflux to the atmosphere(E_A),internal xylem sap transport flux(F_T),and storage flux(DS).Adding those fluxes together provides an estimate of actual stem respiration(R_S).We know that the relative proportion of CO_2 in those fluxes varies greatly among tree species,but we do not yet have a clear understanding of the causes for this variation.One possible explanation is that species differ in stem radial CO_2 conductance(g_c).A high g_c would favor the E_A pathway and a low g_cwould favor the F_Tpathway.However,g_chas only been measured once in situ and only in a single tree species.We measured g_cusing two methods in stems of Fraxinus mandshurica Rupr.(ash)and Betula platyphylla Suk.(birch)trees in situ,along with R_S,E_A,F_T and DS.Stem radial CO_2 conductance was substantially greater in ash trees than in birch trees.Corresponding to that finding,in ash trees over 24 h,E_Aconstituted the entire flux of respired CO_2 ,and F_Twas negative,indicating that additional CO_2 ,probably transported from the root system via the xylem,was also diffusing into the atmosphere.In ash trees,F_T was negative over the entire 24 h,and this study represents the first time that has been reported.The addition of xylem-transported CO_2 to E_A caused E_Ato be 9% higher than the actual R_Sover the diel measurement period.Birch trees,which had lower g_c,also had a more commonly seen pattern,with E_A accounting for about 80% of the CO_2 released from local cell respiration and F_T accounting for the remainder.The inorganic carbon concentration in xylem sap was also lower in ash trees than in birch trees:2.7 versus 5.3 mmol L^(-1),respectively.Our results indicate that stem CO_2 conductance could be a very useful measurement to help explain differences among species in the proportion of respired CO_2 that remains in the xylem or diffuses into the atmosphere.
文摘We report combination of explants and enzymatic protocol as mixed enzymatic-explant procedure to faster extraction of MSCs from WJ. Umbilical cords (UC) were collected from Imam Khomini Hospital. For explant outgrowth, 6 - 9 pieces of WJ were transferred onto tissue culture flask and waited for attachment. For mixed enzymatic-explant, 1 cm3 pieces WJ were placed in enzymatic cocktail comprising 4 mg/ml Collagenase Type I and 1 mg/ml Hyaluronidase and 0.1% trypsin-EDTA. Then isolated cells were analyzed for surface cell markers such as CD73, CD31. Isolated 1.0 × 106 MSCs/ml were encapsulated in alginate hydrogel. Cells with MSCs phenotype were isolated from mixed enzymatic-explant and explant procedures within 24 - 48 hrs and 7 - 10 days, respectively. Both of procedures were shown to form clumps and colonies with dense centers. Phenotypic changes gradually appeared as round cell in UC pieces into homogeneous spindle-shaped and typical fibroblast-like shape cells. By using flow cytometery MSCs showed positive for CD73, and negative for CD31. the morphology of viable MSCs in the beads did not significantly show a different morphology pattern before and after the bead formation process. These findings are indicated that when mixed enzymatic-explant procedure is performed MSCs can be isolated faster and much higher from WJ. These finding is important in comparing with time consuming explants culture for isolation of MSCs.
