Effects of water and salt for groundwater-soil systems on root growth and architecture of Tamarix chinensis in the Yellow River Delta,China

To test the patterns of the root morphology and architecture indexes of Tamarix chinensis in response to water and salt changes in the two media of the groundwater and soil,three-year-old T.chinensis seedlings were chosen as the research object.Groundwater with four salinity levels was created,and three groundwater level(GL)were applied for each salinity treatment to measure the root growth and architecture indexes.In the fresh water and brackish water treatments,the topological index(TI)of the T.chinensis roots was close to 0.5,and the root architecture was close to a dichotomous branching pattern.In the saline water and saltwater treatments,the TI of the T.chinensis roots was large and close to 1.0,and the root architecture was close to a herringbone-like branching pattern.Under different GLs and salinities,the total root length was significantly greater than the internal link length,the external link length was greater than the internal link length,and the root system showed an outward expansion strategy.The treatment with fresh water and a GL of 1.5 m was the most suitable for T.chinensis root growth,while the root growth of T.chinensis was the worst in the treatment with saline water and a GL of 0.3 m.T.chinensis can adapt to the changes in soil water and salt by regulating the growth and morphological characteristics of the root system.T.chinensis can adapt to high-salt environments by reducing its root branching and to water deficiencies by expanding the distribution and absorption area of the root system.

Stable isotope analysis of water sources for Tamarix laxa in the mega-dunes of the Badain Jaran Desert, China

The complex interactions in desert ecosystems between functional types and environmental conditions could be reflected by plant water use patterns. However, the mechanisms underlying the water use patterns as well as the water sources of Tamarix laxa in the mega-dunes of the Badain Jaran Desert, China, remain unclear. This study investigated the water sources and water use patterns of T. laxa using the stable oxygen isotope method. The δ18O values of xylem water, soil water in different layers(0–200 cm), rainwater, snow water, lake water, atmospheric water vapor, condensate water, and groundwater were measured. The sources of water used by T. laxa were determined using the IsoSource model. The results indicate that T. laxa mainly relies on soil water. At the beginning of the growing season(in May), the species is primarily dependent on water from the middle soil layer(60–120 cm) and deep soil layer(120–200 cm). However, it mainly absorbs water from the shallow soil layer(0–60 cm) as the rainy season commences. In September, water use of T. laxa reverts to the deep soil layer(120–200 cm). The water use patterns of T. laxa are closely linked with heavy precipitation events and soil water content. These findings reveal the drought resistance mechanisms of T. laxa and are of significance for screening species for ecological restoration.

Stable oxygen-hydrogen isotopes reveal water use strategies of Tamarix taklamakanensis in the Taklimakan Desert, China

Tamarix taklamakanensis,a dominant species in the Taklimakan Desert of China,plays a crucial role in stabilizing sand dunes and maintaining regional ecosystem stability.This study aimed to determine the water use strategies of T.taklamakanensis in the Taklimakan Desert under a falling groundwater depth.Four typical T.taklamakanensis nabkha habitats(sandy desert of Tazhong site,saline desert-alluvial plain of Qiemo site,desert-oasis ecotone of Qira site and desert-oasis ecotone of Aral site)were selected with different climate,soil,groundwater and plant cover conditions.Stable isotope values of hydrogen and oxygen were measured for plant xylem water,soil water(soil depths within 0–500 cm),snowmelt water and groundwater in the different habitats.Four potential water sources for T.taklamakanensis,defined as shallow,middle and deep soil water,as well as groundwater,were investigated using a Bayesian isotope mixing model.It was found that groundwater in the Taklimakan Desert was not completely recharged by precipitation,but through the river runoff from snowmelt water in the nearby mountain ranges.The surface soil water content was quickly depleted by strong evaporation,groundwater depth was relatively shallow and the height of T.taklamakanensis nabkha was relatively low,thus T.taklamakanensis primarily utilized the middle(23%±1%)and deep(31%±5%)soil water and groundwater(36%±2%)within the sandy desert habitat.T.taklamakanensis mainly used the deep soil water(55%±4%)and a small amount of groundwater(25%±2%)within the saline desert-alluvial plain habitat,where the soil water content was relatively high and the groundwater depth was shallow.In contrast,within the desert-oasis ecotone in the Qira and Aral sites,T.taklamakanensis primarily utilized the deep soil water(35%±1%and 38%±2%,respectively)and may also use groundwater because the height of T.taklamakanensis nabkha was relatively high in these habitats and the soil water content was relatively low,which is associated with the reduced groundwater depth due to excessive water resource exploitation and utilization by surrounding cities.Consequently,T.taklamakanensis showed distinct water use strategies among the different habitats and primarily depended on the relatively stable water sources(deep soil water and groundwater),reflecting its adaptations to the different habitats in the arid desert environment.These findings improve our understanding on determining the water sources and water use strategies of T.taklamakanensis in the Taklimakan Desert.

Spatio-temporal variations of soil water content and salinity around individual Tamarix ramosissima in a semi-arid saline region of the upper Yellow River, Northwest China

Ecological restoration by Taman＇x plants on semi-arid saline lands affects the accumulation, distribution patterns and related mechanisms of soil water content and salinity. In this study, spatio-temporal variations of soil water content and salinity around natural individual Tamarix ramosissiraa Ledeb. were invetigated in a semi-arid saline region of the upper Yellow River, Northwest China. Specifically, soil water content, electrical conductivity （EC）, sodium adsorption ratio （SARa）, and salt ions （including Na＋, K＋, Ca2＋, Mg2＋ and 8042-） were measured at different soil depths and at different distances from the trunk of T. ramasissima in May, July, and September 2016. The soil water content at the 20-80 cm depth was significantly lower in July and September than in May, indicating that T. ramosissima plants absorb a large amount of water through the roots during the growing period, leading to the decreasing of soil water content in the deep soil layer. At the 0-20 cm depth, there was a salt island effect around individual T. ramosissima, and the ECe differed significantly inside and outside the canopy of T. ramosissima in May and July. Salt bioaccumulation and stemflow were two major contributing factors to this difference. The SAR at the 0-20 cm depth was significantly different inside and outside the canopy of T. ramosissima in the three sampling months. The values of SAR~ at the 60-80 cm depth in May and July were significantly higher than those at the 0-60 cm depth and higher than that at the corresponding depth in September. The distribution of Na＋ in the soil was similar to that of the SAI, while the concentrations of K＋, Ca2＋, and Mg2＋ showed significant differences among the sampling months and soil depths. Both season and soil depth had highly significant effects on soil water content, ECe and SARa, whereas distance from the trunk of T. ramosissima only significantly affected ECe. Based on these results, we recommend co-planting of shallow-rooted salt-tolerant species near the Tamarx plants and avoiding planting herbaceous plants inside the canopy of T. ramodssima for afforestation in this semi-arid saline region. The results of this study may provide a reference for appropriate restoration in the semi-arid saline regions of the upper Yellow River.

Photosynthetic and water-related physiological characteristics of Periploca sepium in response to changing soil water conditions in a shell sand habitat

This study was performed to observe the effects of water on photosynthesis and water-related physiology in dominant shrubs in shell sand habitats.Four-year-old Periploca sepium seedlings were used as model species.A gradient of 12 water levels was established by artificially supplying the shell sand with water up to saturation and then allowing natural evapotranspiration to occur.The photo synthetic,chlorophyll fluorescence and stem sap flow parameters of P.sepium were measured under a range of water conditions.The different soil water conditions were classified according to the responses of these parameters.(1)With the increase in the relative water content(RWC)of the shell sand,the parameters of leaf photosynthesis,chlorophyll fluorescence and water-related physiology in P.sepium showed significant critical responses.The net photo synthetic rate(Pn),transpiration rate(Tr),instantaneous water use efficiency(WUE),potential water use efficiency(WUEi),maximum photochemical efficiency(Fv/Fm),actual photochemical efficiency(ΦPSII)and daily accumulation of stem sap flow all increased first and then decreased with increasing RWC,but the corresponding water conditions associated with their maximum values were not the same.An RWC of 69.40%was determined to be the optimal water condition for photosynthesis and water-related physiological activity in P.sepium.At an RWC of 36.61%,the mechanism of photosynthetic inhibition in P.sepium changed from stomatal limitation to nonstomatal limitation;this was also the minimum water requirement for maintaining normal photo synthetic processes.An RWC of 50.27%resulted in the highest WUE in P.sepium,indicating that moderate drought stress increased WUE.(2)Based on the quantitative relationship between the photo synthetic parameters of P.sepium and the shell sand water gradient,the soil water availability was classified into 6 water grades.The RWC range for maintaining strong photosynthesis and high WUE in P.sepium was 63.22-69.98%.(3)Gas exchange in P.sepium was inhibited under drought and waterlogging stresses.Under these conditions,the photosynthetic electron transport chain was blocked,and the dissipation of light energy as heat increased,which ultimately led to a decline in photo synthetic productivity;moreover,transpiration and dissipation were aggravated,and water transmission and utilization processes in P.sepium were hindered.A significant negative feedback regulation mechanism in the photosynthetic and water-related physiological processes of P.sepium was observed;this mechanism allowed P.sepium growing in shell sand to be highly adaptable to water stress.

不同时期水分胁迫对御旱基因型大豆生理特性和产量的影响

为探讨御旱基因型大豆应答干旱胁迫生理和产量的响应机制,以御旱型辽豆14和干旱敏感型辽豆21为试验材料,分析不同生长阶段及抗性品种间的变化规律。2021和2022年连续两年分析水分胁迫对大豆株高、叶面积指数、叶绿素含量、器官生物量、器官含水量、根冠比等生理特性,产量及相关性状的影响。结果表明:随着生育进程的推进,各处理植株的株高、叶面积指数、各器官生物量逐渐累积,整体表现为:鼓粒期>结荚期>开花期>营养生长期。各个时期控水土壤干旱胁迫使植株的叶绿素含量、叶面积指数、株高、各器官含水量降低,但使植株的根冠比提高。相同水分条件下,叶绿素含量整体表现为辽豆21>辽豆14。植株各器官含水量表现为辽豆14>辽豆21。2021年结荚期和鼓粒期控水时,辽豆14的叶面积指数和株高高于辽豆21。同一时期控水,土壤水分提高使大豆根、茎、叶、叶柄、荚皮的干重提高,2020年结荚期和鼓粒期控水时,御旱基因型辽豆14的叶柄干重均显著高于干旱敏感型辽豆21。适宜土壤水分含量条件下两个品种的单株荚数、单株粒数和单株产量较高。各个时期控水,品种差异均显著影响大豆的单株荚数、单株粒数、百粒重和单株产量。同一时期相同水分条件下,大豆的单株荚数、单株粒数和单株产量表现为:辽豆14>辽豆21;而百粒重则表现为:辽豆21>辽豆14。本研究揭示了御旱基因型大豆应答干旱胁迫的生理特征,对指导我国大豆抗旱生产栽培具有重要的理论价值。

不同氮磷钾配比水溶肥对生姜光合生理特性及产量的影响

以“冀姜5号”为试材,在生姜小培土至根茎膨大期施用高氮型(T_(1),N-P-K=30-10-20)、高钾型(T_(2),N-P-K=15-6-30)和高磷型(T_(3),N-P-K=10-30-20)3种水溶肥处理,研究不同水溶肥对生姜生长、光合生理特性以及产量的影响。结果表明,各处理中以T_(2)处理茎粗、分枝数和叶面积最高,株高与其他处理差异不显著。与常规施肥(CK)相比,T_(2)处理显著提高了生姜叶片叶绿素含量、净光合速率、气孔导度和蒸腾速率,叶片蔗糖合成酶、谷氨酰胺合成酶和硝酸还原酶活性明显升高,单株根茎鲜重和产量显著增加。与CK相比,T_(1)处理生姜株高显著增加,茎粗显著降低,净光合速率显著提高,叶绿素含量和碳氮代谢相关酶活性与CK无显著差异,产量显著低于T_(2)处理,与CK差异不显著。T_(3)处理各生长指标及光合生理指标均与CK无显著差异,产量显著低于T_(2)和T_(1)处理,与CK差异不显著。因此,在小培土至根茎膨大期,建议施用高钾型水溶肥(N-P-K=15-6-30),能够有效促进生姜生长,提高叶片叶绿素含量、光合效率及碳氮代谢相关酶活性,有利于生姜增产。

干旱胁迫对6个品种大果沙枣幼苗生理特性的影响

对比分析不同品种大果沙枣应对干旱胁迫的生理响应对策,选育出抗旱性较强的品种,以期为大果沙枣优良品种在干旱区的推广种植提供科学依据。本研究以6个大果沙枣优良品种的1龄扦插苗为研究材料,通过土壤持续干旱后复水处理,采用单因素方差分析比较6个品种大果沙枣幼苗水分生理、叶绿素荧光特性差异,采用隶属函数进行综合评价。结果表明,随着干旱持续时间的延长,6个品种大果沙枣叶片相对含水量(RWC)、枝条水势(PW)、最大光化学效率(Fv/Fm)、实际光能转化效率[Y(Ⅱ)]、光合电子传递速率(ETR)逐渐下降,复水后各项指标均逐渐回升;叶片水分饱和亏(RWD)与初始荧光(F0)随着干旱胁迫时间的延长逐渐增大,复水后减小。参试大果沙枣幼苗抗旱能力由强到弱表现为‘金莎’、‘巴楚1号’、‘雅丰’、‘策勒大黄’、‘白沙甜’、‘麦盖提3号’。在气温较高且大果沙枣幼苗生长旺盛的7—8月,各品种灌溉周期建议为‘麦盖提3号’与‘白沙甜’15d,‘巴楚1号’、‘雅丰’和‘策勒大黄’20d,‘金莎’25d。

深远海浮式风电装备对徐闻附近海域优势物种生理生化指标的影响

[目的]研究深远海浮式风电的建设及运营对周边海域渔业资源的影响。[方法]对徐闻罗斗沙海域深远海浮式风电装备机位点附近海域的S1站点(距机位点约4 km处)和S3站点(距机位点约5 km处)进行拖网取样,选择优势物种南洋舌鳎(Cynoglossidae lida)和哈氏仿对虾(Parapenaeopsis hardwickii)为试验对象,探讨深远海浮式风电装备运行对优势物种生理生化指标的影响。[结果]S3站点南洋舌鳎肝脏中褪黑素(MT)、多巴胺(DA)、白蛋白(ALB)、5-羟色胺(5-HT)含量及半胱氨酸蛋白酶3(Casp-3)、酸性磷酸酶(ACP)活性显著高于S1站点(P<0.05),S3站点南洋舌鳎鳃中ALB含量及Casp-3、碱性磷酸酶(ALP)、ACP活性显著高于S1站点(P<0.05);S3站点哈氏仿对虾肝胰腺中DA、ALB、5-HT含量及Casp-3、ALP、ACP活性显著高于S1站点(P<0.05),S3站点哈氏仿对虾鳃中MT、ALB含量及ALP、ACP活性显著高于S1站点(P<0.05)。[结论]深远海浮式风电在一定范围内对徐闻附近海域优势物种的生理生化指标有一定的影响。

古尔班通古特沙漠西南缘多枝柽柳生理特性对沙堆不同堆积阶段的响应

多枝柽柳作为干旱荒漠区重要的防风固沙灌木,其长期与风沙作用过程中形成了柽柳灌丛沙堆,在维持区域生态环境稳定及遏制沙漠蔓延方面发挥着重要作用。以古尔班通古特沙漠西南缘地区不同发育阶段沙堆上生长的多枝柽柳(Tamarix ramosissima)为研究对象,以空间序列代替时间序列的方法模拟沙堆堆积发育过程,揭示多枝柽柳生理特征对沙堆不同堆积发育阶段的响应及适应机制。结果表明:(1)在沙堆堆积发育过程中,多枝柽柳叶片相对含水量(RWC)及自由水/束缚水(Vs/Va)均呈先上升后下降的变化,其中,在增长阶段沙堆上最高,衰退阶段沙堆上最低,水分饱和亏(WSD)则呈相反趋势;组织含水量(TWC)呈逐渐上升的变化,清晨水势(Ψ_(PD))及正午水势(Ψ_(MD))呈逐渐降低的变化。(2)在沙堆堆积发育过程中,多枝柽柳的光合有效辐射(PAR)、叶片温度(TL)、光合电子传递速率(ETR)以及调节性能量耗散[Y_((NPQ))]日变化均呈先上升后下降的变化,衰退阶段沙堆上多枝柽柳各参数的日均值最大;各发育阶段沙堆上多枝柽柳的非调节性能量耗散[Y_((NO))]日变化均呈先下降后上升的变化,实际光化学效率[Y_((II))]日变化均呈“N”型,且Y_((II))日均值大小依次为增长阶段沙堆(0.489)>稳定阶段沙堆(0.463)>雏形阶段沙堆(0.455)>衰退阶段沙堆(0.439)。(3)气温(TEMP)和PAR与叶片Y_((II))均呈显著负相关,与ETR均呈显著正相关;Y_((II))与ETR、Y_((NO))与Y_((NPQ))均呈现显著负相关;PAR、TEMP是影响不同堆积阶段沙堆上多枝柽柳生理特性的主要环境因子。综合分析表明,在沙堆堆积发育过程中,多枝柽柳可通过调节光合作用和水分利用之间的协同关系来响应微环境的变化,从而减少其脱水风险以实现最大程度资源利用。

不同灌溉模式对籼粳杂交稻甬优1540产量与水分利用效率的影响

旨在探讨不同灌溉模式对籼粳杂交稻甬优1540产量与水分利用效率的影响,并阐明其相关生理基础。本研究以甬优1540为材料,设置了3种灌溉模式,即长淹灌溉(continuous flooding,CF)、轻度干湿交替灌溉(alternate wetting and moderate drying, AWMD)以及重度干湿交替灌溉(alternate wetting and severe drying, AWSD)。研究结果表明,与CF相比, AWMD与AWSD均能显著提高水分利用效率,增幅分别为22.6%~25.6%与18.2%~23.1%;AWMD可以显著提高水稻产量,增幅为8.6%~10.0%,而AWSD则显著降低水稻产量,降幅为6.0%~7.5%。与CF相比, AWMD显著降低了拔节期水稻的茎蘖数、地上部干物质重、叶面积指数、移栽至齐穗期的光合势以及移栽至拔节期的作物生长速率,但显著提高了茎蘖成穗率、拔节至齐穗期的作物生长速率、主要生育期水稻根长密度、深根比、比根长、根系总吸收表面积与活跃吸收表面积,以及灌浆后2次土壤复水期的剑叶净光合速率、根系氧化力、根系与叶片中玉米素和玉米素核苷(Z+ZR)含量、籽粒中蔗糖-淀粉代谢途径关键酶活性等指标。以上结果表明, AWMD可以协同提高甬优1540产量与水分利用效率,优化根-冠生长发育特征,提高灌浆期植株生理活性,实现高产与水分高效利用,为本研究最佳水分管理模式。

投喂频率对工厂化循环水养殖星康吉鳗生长、生理指标及其水质的影响

本研究采用生理学和实验生态学方法探究了工厂化循环水养殖模式下,不同投喂频率对星康吉鳗(Conger myriaster)生长、生理指标以及水质因子的影响。选用初始体重为(150.64±5.43)g的星康吉鳗为研究对象,实验共设2组,分别为1次/天(T1组)、2次/天(T2组),每组3个重复,实验周期为70d。实验每14d检测各养殖池实验鱼平均体重和循环水系统水质指标;实验结束时,采集星康吉鳗血液、组织相关样品,用于生长、生理指标的测定与分析。结果显示,T2组终末体重(FBW)、终末体长(FBL)、增重率(WGR)、特定生长率(SGR)显著高于T1组(P<0.05),T1组饲料系数(FCR)显著高于T2组(P<0.05)。T1组血清丙二醛(MDA)显著高于T2组(P<0.05),T2组肝脏谷草转氨酶(AST)、肝脏谷丙转氨酶(ALT)、肠道胰蛋白酶(TPS)显著高于T1组(P<0.05)。T1组、T2组出口水NH_(4)^(+)-N、NO_(2)^(-)-N 24 h变化中分别有1处(24:00)和2处峰值(20:00、次日8:00);2个实验组出口水24 h内NH_(4)^(+)-N与生物滤池出口水差异显著(P<0.05);生物滤池出口水NO_(2)^(-)-N在04:00、08:00显著低于其他2个实验组出口水(P<0.05);T2组2种指标的24 h变化幅度均小于T1组。整个实验周期内各水质指标均维持在安全养殖范围内,其中,在第70天时,T2组总氮(TN)、总磷(TP)显著高于T1组(P<0.05);生物滤池对各项水质指标处理效果各不相同,其中,对NH_(4)^(+)-N的处理效果最佳,最高可达54.23%。基于上述结果,星康吉鳗幼鱼工厂化循环水养殖模式中,2次/天的投喂效果优于1次/天。相关结果为星康吉鳗工厂化循环水养殖模式中适宜的投喂策略提供了理论参考。

Influence of Water Stress on the Physiological and Biochemical Characteristics of Scutellaria Baicalensis Georgi

Previous studies have shown that water stress can stimulate biosynthesis of secondary metabolites,and physiological and biochemical characteristics of plant can play a key role in its defense responses to water stress.So the physiological and biochemical characteristics of potted Scutellaria baicalensis Georgi plants were investigated under continuous water stress condition.The results showed that the water content in roots,stems and leaves,together with chlorophyll content of the leaves decreased as the water stress strengthened.Simultaneously,the specific leaf weight increased,and the content of proline and soluble sugar in Scutellaria baicalensis Georgi leaves increased significantly.The changing trends of the baicalin content in the roots,stems and leaves of Scutellaria baicalensis Georgi were different.It increased continuously in roots,while ascended constantly in the stems and leaves during the early days under the water stress,but decreased sharply under the heavy stress.In conclusion,proline and soluble sugar had a close correlation with the drought resistance of Scutellaria baicalensis Georgi.Moderate drought is in favor of synthesizing the secondary metabolites.

不同生育期水分胁迫对葡萄生长生理特性的影响

为了研究不同生育期水分胁迫对鲜食葡萄光合作用和果实品质的影响,以玫瑰香葡萄为对象开展设施研究,在萌芽期、新梢生长期、开花期、果实膨大期、着色期以及全生育期分别进行水分胁迫,并以全生育期充分灌溉作为对照组,研究不同生育期水分胁迫对葡萄光合特性、产量和果实品质的影响。结果表明:新梢生长期葡萄叶片净光合速率受水分胁迫影响最小,与对照组相比减小8.96%;果实膨大期葡萄叶片净光合速率受水分胁迫影响最大,与对照组相比减小13.14%;萌芽期水分胁迫提产效果显著,可增产9.87%;着色期水分胁迫有利于果实维生素C以及还原糖的积累,降低可滴定酸的含量,提升果实品质,且对产量无显著影响。

黄河三角洲湿地柽柳周边土壤的水盐耦合关系

为揭示滨海湿地植物对土壤水盐的影响机制,以黄河三角洲湿地柽柳(Tamarix chinensis Lour.)周边土壤水、盐为研究对象,分析柽柳周边土壤水盐相互影响的耦合关系。结果表明:距柽柳远近不同,土壤含水率的差异明显不同,冠下表层土壤含水率明显大于冠缘和裸地,呈现由冠下至裸地逐渐减小的趋势,尤其是柽柳西、南两侧的变化趋势最为明显;20 cm土层以上水分聚集率为冠下大于冠缘,呈现明显的“水岛”效应,而20 cm以下水分聚集率的变化则相反;土壤盐分表聚性显著,远离柽柳的裸地表层土壤含盐量较高,西、南两侧最为明显;土壤总盐与Cl^(-)、Na^(+)、Mg^(2+)3种离子相关性极显著,这些离子在近柽柳周围土壤的变化幅度及含量均较小,盐分富集率明显为冠下小于冠缘,呈现“盐谷”效应;土壤水盐耦合度在柽柳周边表现为西侧>南侧>北侧>东侧,水、盐呈显著负相关;西、南两侧较高的土壤含盐量出现在低含水率的条件下,呈现高含盐量+低含水率为高耦合度的特征,这种高耦合度情况还出现在柽柳周边的表层土壤与远离柽柳的裸地。在柽柳的影响下,水盐耦合度呈现距柽柳由近及远逐步增大、随着土层深度的增加而逐渐减小的趋势。

Study on the Changes of Physiological Indexes of Water Spinach in Eutrophication Water

[Objective] Effect of hypoxic water culture on physiological characteristic of water spinach and its hypoxia tolerance were studied.[Method] Water spinach was planted in soil and eutrophication water by means of floating bed,respectively,and the change of physiological indexes including chlorophyll,proline（Pro）,malondialdehyde（MDA）,soluble sugar and soluble protein in water spinach leaves at mature stage was researched,while the hypoxia tolerance of water spinach and the effect of plant density on water spinach growth were discussed in our paper.[Result] In the hypoxic eutrophication water,the content of total chlorophyll,malondialdehyde,soluble sugar and soluble protein in water spinach leaves was lower than that of soil culture,with higher proline content,which showed that water spinach had better tolerance to hypoxic eutrophication water;the higher the plant density,the lower the chlorophyll content in water spinach leaves,and there was no significant effect of plant density on proline and malondialdehyde content,while soluble protein content was higher under high plant density.[Conclusion] The best plant density of water spinach was 66 plants per floating bed with the area of 2 m2,which could provide theoretical basis for the application of water spinach in floating bed.

‘娇红1号’红花玉兰对水分胁迫的生理响应

以‘娇红1号’1年生嫁接苗为试材,设置盆栽土壤含水量为田间最大持水量(FWC)的20%(HD)、40%(LD)、60%(CK)、80%(LF)、100%(HF)5个处理,测定不同处理条件下‘娇红1号’叶片的光合特性和生理指标分析‘娇红1号’红花玉兰对水分胁迫的生理响应,探究‘娇红1号’红花玉兰在江西等江南丘陵区的引种效应。结果表明:在水分胁迫下,HD处理下的‘娇红1号’苗木在胁迫第10天全部死亡(其余的存活率为100%),CK下‘娇红1号’叶片的叶绿素含量先降后升,其余处理都随着胁迫时间的加长而降低。P_(n)和G_(s)的日变化出现双峰现象,T_(r)日变化呈现先升后降趋势,C_(i)日变化呈现上升趋势,WUE和L_(s)的日变化呈现下降趋势。CK处理的P_(n)、G_(s)、C_(i)和T_(r)日均值最大,HF处理下WUE和L_(s)最大。随着胁迫时间的延长,‘娇红1号’苗木叶片可溶性糖、可溶性蛋白和MDA含量呈现先升后降的变化趋势。Pro含量和SOD活性呈现上升趋势。APX活性呈现先降后升再降的变化趋势,且在胁迫维持到第40天时CK处理下最低。可见,60%~80%FWC的条件下最利于‘娇红1号’红花玉兰的生长。

运输水温对曼氏无针乌贼成体死亡率及生理指标的影响

增殖放流是曼氏无针乌贼(Sepiella japonica)渔业资源修复的重要手段,而水温可能会影响增殖放流运输过程中乌贼的生存状态。为优化曼氏无针乌贼成体增殖放流运输技术,通过实验室内模拟不同水温(14、17、20、23、26、29℃)下的运输过程,分析了不同运输温度下乌贼死亡率和肝脏生理指标的变化。结果显示,运输水温显著影响乌贼成体死亡率(p<0.05),14和29℃处理组的死亡率较高,分别为30.0%和63.3%。相较于20℃处理组,肝糖原含量在14和17℃下显著下降,在29℃下显著上升(p<0.05);乳酸含量在23和29℃下显著上升(p<0.05);超氧化物歧化酶(SOD)活性在17℃下显著下降,在26℃下显著上升(p<0.05);碱性磷酸酶(AKP)活性在各水温下显著下降(p<0.05);随水温变化,谷草转氨酶(AST)活性先下降后上升,而谷丙转氨酶(ALT)活性则先上升后下降。乌贼死亡率与肝脏糖原、乳酸含量和AST活性显著正相关(p<0.05)。研究表明,在5只·L^(-1)密度下水温过低或过高均不适宜乌贼运输,建议水温控制在17~26℃。

遮荫对滨海盐碱地水盐运移及油葵生长和生理的影响

盐碱地是建设光伏的主要土地类型之一。盐碱地光伏系统中光伏组件的遮荫作用会改变局地微气候进而影响土壤水盐动态,系统内作物的生长会受到遮荫和土壤盐分的双重胁迫,阐明遮荫下盐碱地水盐动态和作物生理响应对指导盐碱地光伏农业开发利用具有重要意义。采用大田试验方法,以油葵(Helianthus annuus Linn.)为试验对象,分别设0%、30%、60%和90%遮荫水平,探究遮荫对滨海盐碱地水盐动态及油葵生长特性、光合特性、叶片解剖结构、生物量、籽粒产量及品质的影响,以揭示遮荫下滨海盐碱地水盐运移规律及作物生长和生理变化。结果表明,与无遮荫相比,遮荫能够显著增加滨海盐碱地油葵全生育期内土壤剖面含水量,降低土壤剖面含盐量。遮荫会显著降低油葵净光合速率,抑制茎粗和花盘的生长,减少籽粒粗脂肪,并提高籽粒粗蛋白。弱光下油葵自身会通过增加株高、提高光合色素含量、降低光合色素比值、提高光合酶活性、减小叶片厚度、改变碳同化产物分配方向等方式来促进光合作用。在遮荫率约为30%—60%时,能够增加18%—38%的耕作层土壤含水量,降低6%—18%的耕作层土壤含盐量,并维持15%—38%的油葵生物量和29%—55%的油葵籽粒产量。以上结果表明,遮荫能够改善滨海盐碱地水盐条件,减轻作物盐胁迫,但油葵作为喜光作物,遮荫会显著抑制其光合作用,影响籽粒产量和品质,因此,建议在光伏组件上限遮荫率约为30%—60%的盐碱地光伏系统内种植油葵,以维持油葵的籽粒产量。

西南地区野生岩柿的光合与水分生理特征

以中国西南地区野生岩柿幼苗(Diospyros dumetorum W.W.Smith)为试验材料,探讨岩柿光合与水分生理特征规律,以期为岩柿资源保护、西南地区乡土植物群落修复提供理论和技术支持。分别使用Li-6800便携式光合测定仪和露点水势仪对光合生理指标和叶水势日变化进行测定,苗期岩柿叶片光饱和点为856.7919μmol·m^(-2)·s^(-1),光补偿点为20.4177μmol·m^(-2)·s^(-1),最大净光合速率为9.9469μmol·m^(-2)·s^(-1);其净光合速率主要与大气温度(T_(a))、气孔限制值(L_(s))、叶肉瞬时羧化效率(M_(CE))、蒸腾速率(E)、水分利用效率(W_(UE))、气孔导度(G_(s))影响因子呈正相关,叶片水势与大气温度(T_(a))、大气湿度(R_(H))与光合有效辐射(P_(AR))环境因子有密切关系,苗期岩柿光适应范围较窄,光饱和点及光补偿点偏低,在温度较高、湿度较低、光辐射强的环境下岩柿幼苗吸水能力减弱,使得其幼苗在光辐射强、植被覆盖率低的西南地区较为少见,因此,岩柿更适宜在适度遮荫的林下空间生长,在西南地区进行乡土植物岩柿的培育及经营管理时应进行合理植物配置、建立多层次林分结构,为岩柿幼苗提供一定遮光、降温、增湿的作用,将有助于其发挥更大的生态效益。