CO2浓度升高对2个品种水稻Cu吸收、根形态和植物络合素合成的影响

为探讨CO2浓度升高条件下不同水稻品种粤杂889 (YZ)和荣优398(RY)对耐Cu胁迫性的变化特征,利用水培试验研究不同Cu浓度下CO2浓度升高对2种水稻幼苗生物量、Cu含量、根形态及植物络合素(GSH和PCs)的影响.结果表明,低铜处理对水稻生长具有促进作用,增加2种水稻生物量及根系根毛数、总根长、表面积和体积.随着Cu处理浓度升高,根系GSH和PCs含量分别呈现渐减和渐增趋势.CO2浓度升高条件下,2种水稻生物量显著增加,600 μmol/L Cu处理时增加比例最大,YZ和RY分别增加59.8％和49.0％;水稻根、茎叶Cu含量降低,但根系形态各个指标明显增加,且在高Cu处理下其增加比例较大.CO2浓度升高显著增加根系PCs合成,50 μmol/L Cu处理时增加比例最大,YZ和RY分别增加121.6％,78.7％.在CO2浓度正常与升高条件下,根系GSH、PCs含量与Cu浓度都具有显著相关性.CO2浓度升高通过增加根系形态和PCs含量以增强水稻对Cu的抗逆性,但存在着品种差异,YZ的增加比例大于RY.     

铜胁迫对嫁接和自根黄瓜幼苗光合作用及营养元素吸收的影响

以"新泰密刺"黄瓜/黑籽南瓜嫁接苗和"新泰密剌"自根苗为材料,采用日光温室水培的方法研究了铜胁迫下嫁接对黄瓜幼苗光合作用和营养元素吸收的影响.结果表明,铜(Cu2+)胁迫6 d后,嫁接和自根黄瓜幼苗叶片叶绿素含量和类胡萝卜素含量显著降低;净光合速率和气孔导度显著下降,胞闻CO2浓度随Cu2+离子浓度的增加而降低,但各浓度处理间差异并不显著;电解质渗漏率明显升高,细胞膜透性发生改变;根系和叶片中的营养元素(N、K、Ca、Mg)含量明显降低.嫁接黄瓜幼苗叶片叶绿素和类胡萝卜素含量、净光合速率、营养元素含量显著高于自根黄瓜,电解质渗漏率显著低于自根黄瓜.嫁接黄瓜幼苗叶片中Cu2+含量显著低于自根黄瓜,表明嫁接能够明显减少Cu2+向叶片的运输,缓解Cu2+毒害作用.     

CO2浓度与氮磷供应水平对黄瓜根系生长及各组织矿质养分含量的影响

在开顶式生长箱内，以黄瓜为试验材料，采用营养液培养方法，研究了不同氮水平、磷水平条件下大气CO2浓度对黄瓜植株内矿质养分含量以及根系形态的影响。结果表明：黄瓜植株各部位氮素含量随供氮水平提高而增加，磷水平提高，也能促进各部位氮含量的提高。植株各部位磷含量随供磷水平的提高而升高，在相同磷水平下，缺氮会使各部位磷含量升高。大气CO2浓度升高会使黄瓜植株各部位氮及特定部位的磷含量降低。黄瓜根部的Ca含量随CO2浓度的升高而显著降低，氮和磷水平的升高极显著地增加了其含量，且CO2浓度与供磷水平、供氮与供磷水平以及这三者之间存在明显的交互作用。供氮、供磷水平的升高极显著的提高了黄瓜叶片Ca的含量以及茎部Mg的含量，且两者存在明显的交互作用。黄瓜总根长和总根表面积随CO2浓度的增加有增大的趋势；在缺磷条件下，总根长和总根表面积随氮水平的提高而增大；而同一氮水平和CO2浓度下，磷水平的降低会增加总根长和总根表面积。总体看来，大气CO2浓度的升高能促进黄瓜根系的生长，但会使得黄瓜植株某些部位氮、磷、钙、镁等矿质元素含量降低，而供氮、供磷水平的提高可以通过增强黄瓜的生长与活力促进黄瓜根系对矿质养分的吸收，从而缓解由于CO2浓度升高带来的矿质元素含量降低的风险。这启示我们在对设施蔬菜CO2施肥的同时，也要注重适量提高合理配比下矿质元素的供应。     

CO2与NH4+/NO3-比互作对番茄幼苗培养介质pH、根系生长及根系活力的影响

为探讨CO2浓度升高能否减缓高浓度NH4+-N对番茄根系的毒害作用,本试验在营养液栽培条件下,以番茄为材料,在CO2生长箱中研究2个CO2浓度与5个不同NH4+/NO3-配比的交互作用对生长介质的pH、根系生长及根系活力的影响。结果表明,随着生育期的推进与CO2浓度的升高,pH变化幅度增大。两个CO2浓度均表现为全NO3--N含量营养液的pH呈上升趋势,其它处理营养液的pH均呈现出不同程度的下降趋势,下降的幅度随NH4+/NO3-比例的增加而增加;而且全NH4+-N引起pH值下降的程度大于全NO3--N引起pH增加的程度。CO2浓度升高增加了低NH4+/NO3-比例供应处理的蕃茄幼苗冠干重、根干重、根系活力、根系总吸收面积、活跃吸收面积。这些指标对CO2的响应随NH4+/NO3-比例的降低而加强,冠干重、根干重、根系活力、根系总吸收面积、活跃吸收面积增加分别高达65.8%、78.0%、18.9%、12.9%与18.9%。说明在CO2浓度升高条件下,番茄幼苗根生长潜力在全NO3--N处理中最大,但不能减弱全NH4+-N对番茄根系的毒害作用。     

氯对白菜幼苗的生长及养分吸收的影响

采用土培实验,研究了外源氯（CK,低氯,中氯,高氯）对大白菜 [Brassica campestris L. ssp. Pekinesis (Lour)Olsson]幼苗叶绿素含量、根系活力以及对N、P、K养分吸收、累积的影响。结果表明:低浓度氯处理对大白菜幼苗没有明显的影响。中氯和高氯处理,都显著降低了白菜幼苗生物量、叶绿素含量和根系活力。随着氯浓度的升高,白菜幼苗叶片和根Cl-含量显著升高,中氯处理Cl-累积量最高,过量的氯降低了N、P、K养分在白菜幼苗体内的累积。氯胁迫抑制作物根系活力和光合作用从而减少主动养分的有效供应是造成生物量降低的主要原因。     

盐胁迫下大气CO2浓度升高对黄瓜幼苗生长、光合特性及矿质养分吸收的影响

采用营养液培养和开顶箱法,研究了盐胁迫下CO2浓度升高对黄瓜幼苗生长、光合特性及矿质养分吸收的影响。结果表明,黄瓜生长在80mmol/L NaCl下,其生物量、光合速率、气孔导度、蒸腾速率均显著下降,而胞间CO2浓度明显升高;CO2浓度升高可增加盐胁迫下黄瓜幼苗生物量,使光合速率、气孔导度、蒸腾速率升高。表明CO2浓度升高能减轻盐胁迫对光合功能的不利效应。80mmol/L NaCl可使黄瓜幼苗体内总N和K 的浓度降低,而使Na 浓度增加;CO2浓度升高具有提高盐胁迫下总N和K 浓度,降低Na 浓度的效应,说明CO2浓度升高可减轻盐胁迫的毒害作用,提高黄瓜幼苗生物量。     

CO2浓度升高对水稻生物量及C、N吸收分配的影响

采用FACE(FreeAirCarbon-dioxideEnrichment)技术研究2种N水平下CO2浓度升高对水稻生物量及C、N吸收分配的影响结果表明,与对照相比,高CO2显著降低水稻生物量和C在叶的分配比例,增加其茎、穗和根的分配。高CO2使N在叶的分配降低,穗的分配增加;低N和常规N处理水稻抽穗期根的分配分别降低9.67%和13.1%,其他生育期则增加3.5%~26.6%;拔节期茎的分配分别增加7.03%和5.71%,成熟期分别降低10.5%和7.43%。N水平对水稻生物量和养分分配的影响不显著。     

不同供磷状况下CO2浓度升高对番茄根系生长及养分吸收的影响

采用培养试验研究了磷缺乏与正常供磷条件下,CO2浓度由350μL/L升高至800μL/L苗期番茄的生物量、根系特征和不同器官N、P、K养分含量的变化。结果表明,无论缺磷与否,CO2浓度升高均能显著增加番茄地上部及根系的干物质积累量,提高根冠比。在磷缺乏条件下,CO2浓度升高对番茄根系生长的促进主要表现为增加根系的体积和表面积;而在磷正常供应条件下主要表现为同时增加根体积和分根数,有利于形成强壮的根系。在两种供磷水平下,CO2浓度升高对番茄各器官的N、P、K含量产生不同的稀释效应,但N、P、K总积累量却随CO2浓度升高而显著增加;而且CO2浓度与供P水平对番茄植株的N、P、K积累量具有极显著的正交互效应。     

谷胱甘肽对小麦幼苗铜毒害的缓解作用及其与氮、硫、磷积累的相关性

采用水培法,对外源谷胱甘肽（GSH）缓解小麦幼苗铜毒害及其与氮、硫、磷等元素积累的相关性进行了研究。结果表明,Cu处理（T0组）显著抑制小麦幼苗的生长发育,导致根长、茎叶长、生物量、叶绿素和类胡萝卜素含量以及氮元素积累量下降,诱导了植株蛋白质、内源GSH含量以及硫、磷元素积累量上升。随施用外源GSH浓度的升高,GSH处理（T1、T2、T3组）的小麦幼苗茎叶长、根长、生物量,叶绿素a、b和类胡萝卜素含量、蛋白质含量先上升后下降,内源GSH含量以及氮、硫、磷等营养元素积累量持续上升;其中,T2组小麦幼苗的各项指标与T0组差异均达到显著水平（P〈0.05）,与对照组（CK）无显著差异。外源GSH促进了植株对铜离子的吸收、转运和积累,而外源和内源GSH均与铜胁迫下小麦幼苗氮、硫、磷等营养元素的积累呈极显著正相关（P〈0.01）,其中以T2处理组缓解小麦幼苗铜毒害的作用最显著。     

不同种类蔬菜苗期对镉的敏感性研究

产地环境中镉（Cd）对蔬菜的影响主要表现为蔬菜可食部分超标,高浓度时影响其生长发育,基于评述蔬菜幼苗对Cd的敏感性是按其对Cd的吸收累积量来排序,累积Cd量越高定义为该蔬菜幼苗对Cd越敏感,采用水培方法,探讨了Cd对小白菜（叶菜）、黄瓜、豇豆（果菜）和萝卜（根菜）幼苗吸收累积量及生长发育的影响。结果表明,蔬菜幼苗根和茎叶中累积Cd量均随Cd处理浓度的增加而显著增加（P〈0．05）。同一处理浓度下根中Cd含量远高于茎叶中Cd含量,根和茎叶对Cd的累积强弱顺序也即蔬菜苗期对Cd的敏感性排序为小白菜〉萝卜〉黄瓜〉豇豆;随Cd浓度增加,叶片中叶绿素含量降低,过氧化氢酶（CAT）含量升高;蔬菜出苗率、幼苗根长、植株鲜重显著降低。     

高低应答CO2水稻品种苗期根系对高C环境的响应

本文利用水培试验和琼脂板培养试验研究了高CO₂条件下产量响应存在显著差异的两个水稻品种：II优084(高响应)和武运粳23(低响应),在幼苗期根系形态对高C的响应差异。水培试验结果表明,在幼苗时期,高应答品种II优084在低氮条件下地上部生物量在高CO₂下增加28.5%,根系干物质量对高CO₂响应显著,增幅为28.5%,而其不定根数目没有显著增加,对干物质量响应贡献较大的为总根长。II优084的总根长在高CO₂下增幅为26.3%,不同根粗的根长均有高响应。低应答品种武运粳23低氮下地上部和根系响应不显著,而在正常氮和高氮下则不同。正常氮条件下,地上部对高CO₂响应不显著,而根系生物量在高CO₂下显著增加76.0%,不定根数目增加25.8%,同时总根长增加45.0%,不同根粗的根长均有高响应,II优084则没有显著响应。在高氮条件下,武运粳23地上部生物量在高CO₂下增加35.5%,根系生物量增加80.3%,不定根数目增加38.5%,根系平均直径增加16.7%,总根长无响应,而II优084生物量在高氮下无显著差异。同时,武运粳23在正常氮和高氮下的根系表面积和体积对高CO₂响应也较II优084显著。琼脂板培养试验的结果与水培结果一致,武运粳23根系形态对高浓度蔗糖的响应普遍高于II优084。试验结果说明品种对高C环境的响应特征不随培养条件的变化而变化。与植株生长后期不同,在幼苗期正常氮条件下低应答品种武运粳23的根系生物量和各形态指标对高C的响应明显高于II优084,说明水稻苗期生长响应参数与后期产量响应参数不一定一致,可能是由于苗期生长高响应的品种在营养生长期旺长,反而不利于后期生殖生长,从而导致后期产量的低响应。     

Root biomass dynamics in a semi-natural grassland exposed to elevated atmospheric CO2 for five years

The effects of elevated atmospheric CO₂ on root dynamics were studied in a semi-natural grassland in central Sweden during five consecutive summer seasons. Open-top chambers were used for ambient and elevated (+350 μmol mol^?1) concentrations of CO₂, and chamberless rings were used for control. Root dynamics were observed in situ with minirhizotrons during the five summers and root biomass production was measured with root in growth cores during the last two years, from which total root biomass was estimated for each of the five years. The elevated CO₂ treatment showed both a greater increase in root numbers during the early summer and a greater decline in root numbers during autumn and winter than the ambient CO₂ treatment. Mean root production under elevated CO₂ was 50% greater than ambient CO₂ during the five years, and the difference increased from +25% in the first year to +80% in the last two years. Conversely, during the same period, the elevated to ambient CO₂ difference in shoot biomass decreased from +50% to +5%. This resulted in a dramatic change in root to shoot ratios in elevated CO₂ compared with the ambient treatment, which increased from ?15% in 1996 to +70% in 2000. Similar differences were seen between elevated CO₂ and the chamberless grown control plants, where root to shoot ratios increased steadily from ?47% in 1996 to +27% in 2000. Less dynamically, the root to shoot ratios of ambient CO₂ grown plants compared with the chamberless control plants were consistently ?29%±6% during the experimental period. In conclusion, during the 5 years this grassland was studied, there was a clear shift in plant biomass partitioning from above to below ground for plants exposed to elevated CO₂.     

Two cultivars of peanut (Arachis hypogaea) seedlings show different tolerance to calcium deficiency

The objectives were to determine whether two peanut cultivars show different tolerance to calcium (Ca) deficiency. The seedlings of cultivars LH11 and YZ9102 at first trifoliate leaf stage were transplanted in nutrient solution for 28 days with 0.01 and 2.0 mmol/L Ca treatments. Low Ca supply did not affect plant growth, root length and surface area of YZ9102, whereas decreased plant biomass, root length and surface area of LH11 seedlings that appeared necrosis in shoot tip. YZ9102 plant had higher Ca concentration and more Ca distribution to leaves than LH11. Under limited Ca condition, LH11 appeared net Ca²⁺ effluxes in the zones of 0.2 ～ 1.5 mm from root apex, while YZ9102 roots maintained net Ca²⁺ influxes. Peanut cultivar YZ9102 seedlings had longer roots and higher capacities of Ca uptake and Ca translocation to shoots than LH11, which might be account for higher tolerance to Ca deficiency compared with LH11.     

Effect of carbon dioxide on sorghum yield,root growth,and water use

The concentration of atmospheric carbon dioxide (CO₂) is rising. The effect of higher than ambient levels of CO₂ on plants grown in the sub-humid central Great Plains of the U.S.A. has not been investigated. Therefore, an experiment was conducted at Manhattan, Kansas, to study the effect of elevated levels of CO₂ on grain sorghum [Sorghum bicolor (L.) Moench]. During the summer of 1984, the sorghum was grown in rhizotrons in which root and shoot growth could be monitored throughout the growth cycle. The tops of the plants were enclosed in plastic chambers, which contained one of four concentrations of CO₂ : 330 (ambient), 485, 660, and 795 μl 1⁻¹.Enriched CO₂ delayed the boot, half bloom, and soft dough stages. Sorghum grown at elevated concentrations of CO₂ yielded more roots and shoots than plants grown with 330 μl 1⁻¹. At all soil-profile depths, root numbers and weights were higher at elevated CO₂ than at ambient CO₂. However, water use per unit dry matter of leaf, stem, root, and grain was decreased 13, 30, 31, and 29%, respectively, in plants grown at 795 μl 1⁻¹ CO₂ compared to plants at 330 μl 1⁻¹ CO₂. Although elevated CO₂ levels increased the stomatal resistance and leaf temperature, an increase in leaf area indices resulted in a lower canopy resistance.     

Potassium and cyst nematode effect on nutrition of soybean cultivars with resistance to cyst nematode

Abstract

Greenhouse and laboratory research studied K and CI nutrition of four soybean [Glycine max (L) Merril] cultivars with differential resistance to Soybean Cyst Nematode (SCN, Heterodora glycines Ichinohe). The cultivars: Forrest (Group V, resistant to races 1 and 3), Bradley (Group VI, resistant to races 1, 3 and 4), Essex (Group V, susceptible), and Davis (Group VI, susceptible*) were used. Potassium treatments were zero K, K₂SO₄ and KCI, and SCN treatment was zero and 500 eggs/100 g of previously sterilized soil. Single plants were grown for 30‐days in 400 g of soil in 3.5 cm pots maintained at 23°C. Plants were separated into roots and shoots for analysis. Post harvest SCN cyst counts were completed to evaluate cultivar‐K treatment effect on SCN population dynamics and treatment effects on root and shoot K, Ca, Mg and CI.

Cyst counts were a function of cultivar resistance and inoculation, and were not affected by K treatment. Root and shoot weights of all cultivars were lower In the SCN inoculated pots. Potassium treatments did not alter the SCN negative effect on root weight, but KCI appeared to reverse the negative effect that SCN inoculation had on shoot weight of Bradley. SCN Inoculation appeared to reduce CI concentration in the roots of all cultivars, increase root K of Bradley and no effect on root K of Davis, Essex and Forrest. Transiocation of K from roots to shoots was not adversely affected by SCN inoculation. The KCI treatment increased shoot CI concentration of cultivars in order Essex > Davis > Forrest > Bradley. The order of correlation of root CI concentration with shoot CI concentration was: Essex (r = 0.80**) > Bradley (r = 0.70**) > Davis (r = 0.54**) > Forrest (r = 0.40**) suggesting difference in root CI adsorption characteristcs and CI translocation characteristis to the shoots. Additional research is needed to determine to what extent root and shoot CI accumulation characteristics are related to SCN resistance and if the shoot CI accumulation characteristics is independent of root CI adsorption characteristics.     

Partitioning CO2 Respiration among Soil,Rhizosphere Microorganisms,and Roots of Wheat under Greenhouse Conditions

Abstract

The measurement of soil, root, and rhizomicrobial respiration has become very important in evaluating the role of soil on atmospheric carbon dioxide (CO₂) concentration. The objective of this study was to partition root, rhizosphere, and nonrhizosphere soil respiration during wheat growth. A secondary objective was to compare three techniques for measuring root respiration: without removing shoot of wheat, shading shoot of wheat, and removing shoot of wheat. Soil, root, and rhizomicrobial respiration were determined during wheat growth under greenhouse conditions in a Carwile loam soil (fine, mixed, superactive, thermic Typic Argiaquolls). Total below ground respiration from planted pots increased after planting through early boot stage and then decreased through physiological maturity. Root‐rhizomicrobial respiration was determined by taking the difference in CO₂ flux between planted and unplanted pots. Also, root and rhizomicrobial respirations were directly measured from roots by placing them inside a Mason jar. It was determined that root‐rhizomicrobial respiration accounted for 60% of total CO₂ flux, whereas 40% was from heterotrophic respiration in unplanted pots. Rhizomicrobial respiration accounted for 18 to 25% of total CO₂ flux. Shade and no‐shoot had similar effects on root respiration. The three techniques were not significantly different (p>0.05).     

CO2浓度升高对番茄苗根系生长及其吲哚乙酸和乙烯含量的影响

A hydroponic experiment was carried out to study the effect of elevated carbon dioxide (CO2) on root growth of tomato seedlings. Compared with the control (350 μL L-1), CO2 enrichment (800 μL L-1) significantly increased the dry matter of both shoot and root, the ratio of root to shoot, total root length, root surface area, root diameter, root volume, and root tip numbers, which are important for forming a strong root system. The elevated CO2 treatment also significantly improved root hair development and elongation, thus enhancing nutrient uptake. Increased indole acetic acid concentration in plant tissues and ethylene release in the elevated CO2 treatment might have resulted in enhanced root growth and root hair development and elongation.     

不同供磷状况下CO2浓度升高对番茄根系生长及养分吸收的影响

采用培养试验研究了磷缺乏与正常供磷条件下,CO₂浓度由350μL/L升高至800μL/L苗期番茄的生物量、根系特征和不同器官N、P、K养分含量的变化。结果表明,无论缺磷与否,CO₂浓度升高均能显著增加番茄地上部及根系的干物质积累量,提高根冠比。在磷缺乏条件下,CO₂浓度升高对番茄根系生长的促进主要表现为增加根系的体积和表面积;而在磷正常供应条件下主要表现为同时增加根体积和分根数,有利于形成强壮的根系。在两种供磷水平下,CO₂浓度升高对番茄各器官的N、P、K含量产生不同的稀释效应,但N、P、K总积累量却随CO₂浓度升高而显著增加;而且CO₂浓度与供P水平对番茄植株的N、P、K积累量具有极显著的正交互效应。     

大气CO2浓度升高对植物根系形态的影响及其调控机理

大气CO2浓度升高会对植物根系形态产生明显的影响,尤其是根的长度、分枝、产量、周转以及根与枝的分配模式等方面,从而有助于植物从土壤中摄取更多的养分及水分,更好地适应大气CO2浓度升高后的环境。目前,该领域研究,如在CO2浓度升高条件下,根系形态变化的内部调控机制,以及由其引起的物质分配和能量流动等仍存在较大争议。本文综述了近年来关于CO2浓度升高及与外界环境因素的共同作用对根系形态影响的研究,以期为阐明CO2浓度升高对植物根系生长发育带来的影响及其机制提供理论指导。     

FACE条件下水稻生育后期剑叶光合色素含量及产量构成的响应研究

为明确CO2浓度增高对水稻叶片光合能力的影响,利用自由CO2富集系统(free-air carbon dioxide enrichment,FACE)研究‘松粳9号’和‘稻花香2号’水稻生育后期剑叶光合色素含量及产量构成的变化趋势;通过测定水稻孕穗—抽穗期剑叶叶绿素a、叶绿素b和类胡萝卜素含量,分析光合色素组成、各组分间相关关系及品种间差异;收获后实测产量构成因素,比较处理及品种间差异。结果表明,与对照相比,高CO2浓度下水稻孕穗和抽穗期叶绿素a含量都极显著升高,‘松粳9号’和‘稻花香2号’的最大增幅分别达28.46%和19.58%;抽穗后20 d分别极显著降低15.25%和23.20%。高浓度CO2极显著降低水稻抽穗后20 d叶绿素b含量,两品种降幅分别为7.57%和5.33%;极显著增加抽穗后30 d叶绿素b含量,增幅分别为4.19%和9.46%。高CO2浓度下两品种水稻抽穗期类胡萝卜素含量显著增加9.47%和13.55%,抽穗后10 d之后显著降低,最高降幅达13.54%和16.67%。高CO2浓度下水稻总叶绿素含量和叶绿素a/b比值在孕穗和抽穗期增加,抽穗后20 d减少。高CO2浓度对产量构成因素均有正面影响,增加了水稻单位面积穗数、结实率和千粒重,显著提高了千粒重,两品种增幅分别达8.6%和4.5%。试验结果明确了高CO2浓度对水稻灌浆前期剑叶光合色素的积累有促进作用,后期有抑制作用,品种间响应差异显著;千粒重增加是增产的主要因素。