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1.
升高CO2浓度能够促进作物的光合作用,提高作物的生物量和产量,但关于CO2与NH+4/NO-3比及其交互作用对作物影响的研究较少,为探索番茄幼苗生长发育对CO2浓度升高的响应是否对NH+4/NO-3配比有较强的依赖关系,本试验在营养液栽培条件下,以番茄(Lycopersicun esculentum Mill)为试材,研究正常大气CO2浓度(360 μL/L)和倍增CO2浓度(720 μL/L)与不同NH+4/NO-3配比的交互作用对番茄幼苗生长的影响。结果表明:CO2浓度升高提高了低NH+4/NO-3比例处理中番茄叶片的光合速率和水分利用率,提高幅度随NH+4/NO-3比例的降低而增强,光合速率增强最大达55%。在同一CO2浓度处理下净光合速率与水分利用率均随NH+4/NO-3比例的增加而显著降低。这说明CO2浓度升高对番茄幼苗生长发育的促进作用随NH+4/NO-3比例的降低而提高,但并没有减弱全NH+4-N处理中番茄幼苗的受毒害作用。综上所述,CO2浓度升高能提高植物生产的节水能力和水分生产力;水培条件下,NO-3-N是最适合番茄幼苗生长发育的氮源,其它NH+4/NO-3比例对番茄幼苗的生长发育有一定的抑制作用,仅以NH+4-N作氮源则番茄幼苗很难生长。  相似文献   

2.
空间电场对植物吸收CO2和生长速度的影响   总被引:5,自引:4,他引:5  
为研究空间电场对植物吸收CO2和生长速度的影响,首先采用同位素示踪法,分析了不同空间电场调控营养液栽培的番茄秧吸收CO2气体和HCO3-阴离子的能力,证实了14C-HCO3-是一种受控于空间电场变化的阴离子,且空间电场强度的变化方向调控着14C-HCO3-阴离子流的流动方向.在此基础上以蕹菜(空心菜)为试验材料,采取空间电场与增施CO2浓度的参数组合,做对比生长试验,通过红外线CO2分析法揭示了空间电场的极性对植物吸收CO2的速度有显著影响,且正向空间电场能显著促进植物对CO2的吸收,并得到正向空间电场与足量的CO2浓度相配合能大幅度提高温室蔬菜生长速度,使作物产量倍增的结论,为建立空间电场促进植物生长技术提供理论依据.  相似文献   

3.
在空闲拱棚和黄瓜日光温室内,分别研究了化学反应法(H2SO4+NH4HCO3)、煤球燃烧法和颗粒CO2气肥3种肥源的性能,并与液体CO2进行成本比较,结果表明:化学反应法产气迅速,设备折旧成本较低;煤球燃烧法产气速度中等,原料成本最低;颗粒CO2气肥产气速度较慢且不易调控,原料成本最高。考虑化学反应产物的再利用因素,化学反应法、煤球燃烧法和液体CO2 3种肥源总成本接近,但从生态、节能、成本和效果等方面综合评价,煤球燃烧法原料丰富、成本低廉,较符合我国目前的设施、经济、资源和技术条件。  相似文献   

4.
肥液浓度对单膜孔入渗NO-3-N运移特性影响的室内试验研究   总被引:5,自引:0,他引:5  
该文通过室内入渗试验,研究了不同浓度的单膜孔肥液入渗NO-3-N的分布特性。研究表明:不同浓度的膜孔肥液入渗土壤NO-3-N浓度的湿润锋运移距离与土壤水分运动的湿润锋一致;肥液浓度越大,相同入渗时间的NO-3-N浓度锋运移距离越大,土壤剖面NO-3-N浓度最大值越大,相同深度处土壤NO-3-N浓度也越大。肥液入渗土壤NO-3-N浓度分布特征与湿润体深度符合分段函数模型。供水入渗过程中,NO-3-N浓度锋运移距离和浓度最大值均随时间的延长而增大;再分布过程中,NO-3-N浓度锋运移距离继续增大,而NO-3-N浓度最大值逐渐减小。  相似文献   

5.
该文采用中国农业大学农业部设施农业生物环境工程重点开放实验室研制的设有组培微环境实时监控系统的大型组培箱,分别对矮牵牛、菊花和番茄组培苗移栽后箱体内CO2浓度的变化规律及不同CO2增施浓度对无糖组培苗生长的影响进行了研究。试验表明:移栽后的当天,组培箱内的CO2浓度便开始下降,第2 d下降速度明显加快,均降至100 μL/L以下。在移栽后的第4~5 d,箱体内CO2浓度下降到35 μL/L左右后便不再下降,一直在30~40 μL/L之间波动。因此得出:无糖培养在组培苗移栽后的第2 d就应增施CO2,否则会直接影响组培苗的生长。在不同CO2增施浓度试验中,当光照度控制在80 μmol/(m2·s)时,CO2浓度为(650±50)μL/L时培养出的组培苗生长状况最好。  相似文献   

6.
3 种挺水植物吸收水体NH4+、NO3-、H2PO4- 的动力学特征比较   总被引:2,自引:1,他引:2  
本文用动力学试验研究了具有景观价值的3 种挺水植物—— 水生美人蕉(Canna generalis)、细叶莎草(Cyperus papyrus)、紫芋(Colocasia tonoimo)对H2PO4-、NH4+、NO3- 的吸收特征及差异。试验结果表明: 3 种挺水植物吸收H2PO4- 时, 美人蕉的吸收速率最快, 且在较低离子浓度条件下也可以吸收该离子, 说明其具有嗜磷特性, 能够适应广范围浓度H2PO4- 环境; 吸收NO3- 时, 细叶莎草的速率最快, 但对低浓度NO3- 环境的适应能力较差, 美人蕉吸收NO3- 的特性与细叶莎草刚好相反; 吸收NH4+ 时, 细叶莎草的吸收速率最快, 且在低浓度NH4+ 环境下仍能吸收该离子, 而美人蕉的吸收速率最慢, 但能在低浓度NH4+ 环境下吸收该离子。说明不同植物对养分的吸收特性存在较大差异, 各自的污染水体修复适用范围也不同。美人蕉可用于各种浓度H2PO4- 污染的水体修复; 而NO3- 污染严重的水体最适宜用细叶莎草作先锋植物, 修复到一定程度后再种植美人蕉来维持水质; 细叶莎草在各种浓度NH4+ 污染的水体中均适用, NH4+ 污染较轻的水体也可用美人蕉修复。  相似文献   

7.
由于人类大量开采使用石油、煤炭、天然气等化石燃料,使大气CO2浓度升高,这不但加速全球变暖,还将影响地球上动植物的生存和分布,从而对整个生态系统产生深远影响。为探明CO2浓度升高与豌豆蚜(Acyrthosiphon pisum)虫口密度对紫花苜蓿(Medicago sativa)叶片内化学物质的影响,明确CO2浓度升高和蚜虫密度在紫花苜蓿生理生化中的作用,试验在CO2光照培养箱内设置380 μL·L-1(对照)、550 μL·L-1和750 μL·L-1 3个CO2浓度培育苜蓿幼苗并接入10日龄成蚜10头·株-1、20头·株-1、30头·株-1,并以0头·株-1作为空白对照,1周后测定植物体内营养物质和次生代谢物质含量。结果表明,随CO2浓度升高,蚜虫密度为30头·株-1时紫花苜蓿可溶性蛋白、可溶性糖以及淀粉含量均上升,在750 μL·L-1 CO2浓度下分别比CK上升11.62倍、0.49倍和0.24倍;黄酮、总酚和简单酚含量也显著上升。随蚜虫危害程度加重,同一CO2浓度下紫花苜蓿淀粉、简单酚含量先上升后下降,高CO2浓度蚜虫密度为30头·株-1时比0头·株-1时可溶性糖、总酚以及单宁含量上升1.66倍、1.49 mg·g-1和1.09 mg·g-1,差异均显著(P<0.05)。说明具有固氮作用的豆科植物更易于适应CO2浓度升高的变化,从而在受到刺吸胁迫后增强自身诱导抗虫性以抵御害虫为害。  相似文献   

8.
为提高Cd污染土壤植物修复效率, 采用盆栽方法研究了Cd含量为10.0 mg·kg-1的土壤中, 伴随阴离子肥料和间作鹰嘴豆对油菜生长与吸收积累Cd的影响。结果表明: 单作下, 不同肥料处理土壤DTPA提取态Cd含量为Cl->NO3->SO42- >无伴随阴离子; 间作鹰嘴豆提高土壤DTPA提取态Cd含量, 且伴随C1-、SO42- 或NO3- 条件下达显著水平。单作下, 油菜主根长为NO3- >C1- >SO42- >无伴随阴离子, 根系体积为SO42->NO3- >C1- >无伴随阴离子, 根系活力NO3 >SO42 >Cl >无伴随阴离子; 间作鹰嘴豆在无肥处理下可显著提高油菜的主根长与根系体积, 在无肥处理、SO42- 、NO3- 处理下显著提高根系活力。单作下, 油菜地上部Cd含量表现为C1- >SO42- >NO3- >无伴随阴离子, 间作鹰嘴豆可显著降低无肥处理地上部Cd含量, 但显著提高施肥处理地上部的Cd含量。单作下, 施肥可显著增加油菜的Cd积累总量, 以伴随C1-处理最大, 达470.4 μg·plant-1; 间作鹰嘴豆也可提高油菜的Cd积累总量, 且伴随C1- 处理最大, 达783.7 μg·plant-1。除伴随C1- 处理外, 施肥处理均可显著提高油菜的Cd转移系数, 施肥处理的Cd转移系数均大于1; 间作鹰嘴豆也可提高油菜的Cd转移系数, 且施肥条件下达显著水平。因此, 如果把油菜用作Cd污染土壤植物修复作物, 可选择施用含Cl 肥料和间作鹰嘴豆, 以提高修复效率。  相似文献   

9.
对宁夏回族自治区银北地区盐碱地野外土壤表层光谱反射率和土壤全盐及盐分进行定量分析,筛选出各土壤盐分指标的敏感波段,然后采用全回归和逐步回归的方法建立各盐分的预测模型。结果表明:表层土壤高光谱反射率r,及其平滑去嗓处理后的值R,lg(R)与全盐含量呈极显著正相关关系,1/R,lg(1/R)与全盐呈极显著负相关关系,(R)'和〔lg(1/R)〕'在特定单波段处表现较佳;土壤表层光谱反射率与CO32-的相关性最强,其次是SO42-;土壤光谱反射率与Na+的相关性在各种变换方法下均较强,其次为Mg2+,与Ca2+的相关性最弱。基于R的逐步回归方程为全盐含量预测的最佳模型;基于土壤光谱反射率拟合土壤CO32-的准确度略高于对土壤HCO3-;敏感波段估测土壤SO42-含量的决定系数明显高于其他阴离子;采用〔lg(1/R)〕'逐步回归得到的方程拟合土壤Na+,K+和Mg2+含量相对于其他变换方式效果更理想。预测模型中对土壤全盐和Na+的模型精度较高,预测能力强;光谱对土壤SO42-和Mg2+的预测能力也较强;对土壤Cl-和Ca2+的预测稳定性、预测能力和精度都较差。  相似文献   

10.
利用开顶式气室和盆栽方法, 以冬小麦品种"小偃6号"和"小偃22"为供试材料, 在2种CO2浓度(375 μL·L-1和750 μL·L-1)和3个施氮水平[0、0.15 g(N)·kg-1(土)和0.30 g(N)·kg -1(土)]下分析了小麦抽穗期绿色叶片、非叶光合器官(茎鞘、穗、芒)的形态和光合面积以及粒叶比对CO2浓度升高和施氮的反应。结果表明, 施氮有助于小麦叶和非叶光合器官伸长和增宽(粗), 增加其光合面积、穗粒数、穗粒重、粒数叶比和粒重叶比。与背景CO2浓度(375 μL·L-1)相比, CO2浓度升高对叶片和茎节长度、茎叶和芒光合面积具有明显的正向效应(P<0.05), 但对叶宽、茎节直径、穗面积影响不明显(P>0.05), 使"小偃6号"和"小偃22"单茎光合面积分别增加8.1%~15.1%和2.8%~13.2%, 且均以0.30 g(N)·kg-1(土)施氮水平下增幅最大。CO2浓度升高后, 穗粒数和粒数叶比在3个施氮水平下均不同程度增加, 其中2个品种粒数叶比分别在0.30 g(N)·kg-1(土)和0.15 g(N)·kg-1(土)施氮水平下增加最明显, 增幅分别为44.2%和41.4%; 穗粒重和粒重叶比在不施氮时下降, 在施氮时显著增加, 其中2个品种粒重叶比平均增幅分别为43.6%和20.7%。由于芒面积远小于其他源器官面积, 在单茎光合面积中所占比例较小(3%左右), 因此认为CO2浓度升高主要通过促进小麦茎叶伸长生长来增加光合面积, 同时提高单位叶面积库承载力和物质调运能力, 改善源库关系, 增加氮素供应有利于小麦源库生长对CO2浓度升高的反应。  相似文献   

11.
The absorption and transport of Na and Cl from 0.1 mM and 10 mM 22Na labelled NaCl or 36Cl labelled KCl were examined in 15 days old seedlings of 3 cultivars of rice differing in their tolerance to salinity. Furthermore, the effects of 10, 100 and 1000 ppm (N)2S on their uptake were studied. It was found that in general, the salt‐tolerant cultivars BR and PNL‐1 absorbed more Na and translocated a lesser proportion of it to the shoot, compared to the salt‐sensitive IR‐8, from 0.1 mM NaCl. The presence of (N)2S reduced the uptake of Na in all the cultivars. It was also found that the presence of 100 ppm K, KN or NNreduced Na absorption from 0.1 mM NaCl significantly in all the cultivars, and the translocation to shoot in BR‐ Chloride transport from 0.1 mM NaCl was reduced by (N)2S in all the cultivars. The 3 cultivars differed significantly in the rates of absorption and transport of Na and Cl. The results indicate that PNL‐1 which is a cross of IR‐8 X BR, has inherited the salt tolerance trait from BR. Lower rates of Na translocation to the shoot can be used as an index of salt tolerance in rice.  相似文献   

12.
Recently conventional chemical analyses were mostly replaced by instrumental analysis. Although results from both methods were examined in details after the samples had been solubilized or extracted by appropriate techniques, the solubilization method was considerably altered so as to be convenient for the following analysis. In atomic absorption spectrophotometry (AAS), for example, fusion technique was mostly inadequate because of the higher salts concentration in the obtained solution. The use of H2SO4 must also be avoided in acid digestion for SO4 2- precipitates with Sr2+ or La3+ which must be added to eliminate interferences in the succeeding procedure. Therefore, it is essential to consider the whole scheme including sample treatments to evaluate the suitability of instrumental analysis. In this experiment, the suitability of the methods which have been employed in our laboratory was examined by analyzing 9 rock standards.  相似文献   

13.
We examined the potential of a subsoil to denitrify nitrate under optimal anaerobic conditions in a laboratory-based incubation when supplied with a range of C substrates of increasing recalcitrance. Both topsoil and its associated subsoil were supplied with nitrate and either glucose, starch or cellulose. Microbial respiration and the evolution of N2O and N2 were measured. The subsoil supported low amounts of microbial activity and responded only to the glucose treatment; with less than one-fifth of the N2O production measured in the top soil. Overall, our findings demonstrated that the denitrification potential of this particular subsoil is relatively low and that only simple carbohydrates could be utilised readily by the resident microorganisms.  相似文献   

14.
On examining the changes in lamellae and stroma nitrogen during leaf development, it is demonstrated that the lamellae and stroma fractions ofrice chloroplasts develop in quite different ways. In the case of stroma, the stroma materials existing in the leaf section which has just emerged from a leaf sheath are quite limited and the major part of this fraction is derived from the successive protein synthesis, i.e., the synthesis of this fraction was markedly increased during leaf expansion. This developmental pattern of the stroma coincided with the changes in the high-molecular-weight water soluble leaf protein, which seemed to be mainly composed of Fraction I protein. A rapid increase in stroma nitrogen was found to be a major cause for an increase in the leaf nitrogen content during leaf development.

On the other hand, the developmental pattern of the lamellae fraction was characterized by the fact that a considerable amount of this fraction had already been prepared when a leaf emerged from a leaf sheath and thereafter, no outstanding increase was seen compared to that of the stroma. This developmental pattern of the lamellae fraction resulted in a lowering of the proportion of lamellae nitrogen to the total leaf nitrogen during leaf development.

A great change in the lamellae-stroma composition of chloroplasts was observed. The proportion of stroma nitrogen to the total chloroplast nitrogen tended to increase as a leaf develops. Since the developmental stage varied according to the regions of a leaf, variation of the lamellaestroma composition was seen even within a leaf, i.e., the proportion of stroma nitrogen increased from base to tip.

In order to compare the synthetic rate of chlorophyll with those of the stroma and lamellae fractions, the changes in the ratios of stroma nitrogen/chlorophyll and lamellae nitrogen/chlorophyll were examined. The lamellae nitrogen/chlorophyll ratio decreased as a leaf developed, whereas the stroma nitrogen/chlorophyll ratio increased. Then the synthetic rates of these fractions during leaf development turned out to be of the same order as the stroma fraction, chlorophyll, lamellae fraction.  相似文献   

15.
Abstract

The availability of soil Mn to corn in relation to extractability of soil Mn by EDTA, Mg(NO3)2, CH3COONH4, hydroquinone, H3PO4, and NH4H2PO4 as affected by liming was evaluated under field conditions on a single soil type. EDTA, Mg(NO3)2 and CH3COONH4‐extractable Mn were related inversely to available Mn. No useful relationships were found between hydroquinone, H3PO4, and NH4H2PO4‐extractable soil Mn and Mn uptake by sweet corn.  相似文献   

16.
Abstract

Forest fires can change the greenhouse gase (GHG) flux of borea forest soils. We measured carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) fluxes with different burn histories in black spruce (Picea mariana) stands in interior Alaska. The control forest (CF) burned in 1920; partially burned (PB) in 1999; and severely burned (SB1 and SB2) in 2004. The thickness of the organic layer was 22 ± 6 cm at CF, 28 ± 10 cm at PB, 12 ± 6 cm at SB1 and 4 ± 2 cm at SB2. The mean soil temperature during CO2 flux measurement was 8.9 ± 3.1, 6.4 ± 2.1, 5.9 ± 3.4 and 5.0 ± 2.4°C at SB2, SB1, PB and CF, respectively, and differed significantly among the sites (P < 0.01). The mean CO2 flux was highest at PB (128 ± 85 mg CO2-C m?2 h?1) and lowest at SB1 (47 ± 19 mg CO2-C m?2 h?1) (P < 0.01), and within each site it was positively correlated with soil temperature (P < 0.01). The CO2 flux at SB2 was lower than that at CF when the soil temperature was high. We attributed the low CO2 flux at SB1 and SB2 to low root respiration and organic matter decomposition rates due to the 2004 fire. The CH4 uptake rate was highest at SB1 [–91 ± 21 μg CH4-C m?2 h?1] (P < 0.01) and positively correlated with soil temperature (P < 0.01) but not soil moisture. The CH4 uptake rate increased with increasing soil temperature because methanotroph activity increased. The N2O flux was highest [3.6 ± 4.7 μg N2O-N m?2 h?1] at PB (P < 0.01). Our findings suggest that the soil temperature and moisture are important factors of GHG dynamics in forest soils with different fire history.  相似文献   

17.
The effects of NO2 and O3 exposure alone or in combination were investigated with respect to the amino acid content and composition in kidney bean. The short-term exposure (up to 8 h) to NO2 at a concentration of 4.0 ppm alone or in combination with O3 at a concentration of 0.4 ppm induced a rapid increase in the total amino acid content among which glutamine accounted for most of the part. Total amino acid content was also increased by O3 exposure at 0.4 ppm after 2 hours’ lag period. Ammonium level became higher in the case of combined exposure to NO2 and O3, while it remained constant in the case of exposure to NO2 and O3 alone.

When the exposure period was extended to 2 to 7 days (long-term exposure), the increase in the content of the total amino acids was observed in most of treatments. Roots of the plants exposed to various concentrations of NO2 and O3 showed the most remarkable increase in the content of total amino acids. Asparagine, in place of glutamine, became a major amino acid. The percentage of asparagine was especially increased by the mixed exposure to NO2 and O3 These results indicate that glutamine which accumulates considerably in the early phase of the gas exposure (short-term exposure) seems to be gradually converted into other amino acids, mainly asparagine.

The correlation between the content of each amino acid, ammonium and total amino acids was calculated using data from the above experiment. Most of the amino acids in the primary and trifoliate leaves showed a high correlation with the total amino acids, suggesting that the changes in the amount of total amino acids caused by the air pollutants may be reflected not only by a particular amino acid, but also by an individual amino acid composing soluble metabolite pool. A high correlation was obtained among amino acids belonging to the serine family such as glYCine, serine, and cysteine.  相似文献   

18.
The mechanism of SO2 inhibition of photosynthesis in intact leaves of tomato and maze was studied to evaluate SO2 inhibition of photorespiration. Leaf tissues were fumigated with SO2 under photorespiratory (low CO, and/or high O, concentrations) and non-photo-respiratory conditions. When tomato leaf disks were fumigated with 10 ppm SO2 at 2, 21 and 100° o O., SO2 inhibited photosynthesis at 2% O2 in the same degrees as at 21% O2. SO2 inhibition of photosynthesis was depressed at higher CO2 concentrations when the disks were fumigated with SO2 at different CO2 concentrations. High CO2 concentrations also reduced the photosynthesis inhibition of maize leaf disks. These results suggest that SO2 inhibits photosynthesis through other mechanisms than photorespiration inhibition and confirm the view that SO2 competes with CO2 for the carboxylating enzymes in photosynthesis  相似文献   

19.
Abstract

We investigated the effect of foliar application of potassium nitrate (KNO3) and zinc sulfate (ZnSO4) on the fruit quality of pomegranate (Punica granatum L. cv. Malas-E–Torsh in Saveh). Potassium was applied as KNO3 at concentrations of 0%, 0.25%, and 0.5% and zinc was applied as ZnSO4 at concentrations of 0%, 0.5%, and 1% in a completely randomized block design. To determine the effect of the treatments on fruit quality, we measured fruit weight, peel thickness, aril diameter, phenol content of the juice, pH, total soluble solids (TSS), titratable acidity (TA), and antioxidant capacity. Foliar application of KNO3 significantly increased fruit weight, 100 aril weight, peel weight, peel thickness, TTS, and antioxidant capacity. In contrast, pH, TA, TSS/TA, and phenol content of the juice were not influenced by foliar application of KNO3. ZnSO4 significantly increased fruit weight, aril diameter, and phenol content of the juice. KNO3 1% and ZnSO4 0.5% were identified as the most appropriate treatments in improving quality and quantity of pomegranate. The fatty acid profile of the pomegranate oil was primarily composed of punicic acid, linoleic acid, oleic acid, palmitic acid, and stearic acid.  相似文献   

20.
In order to study effects of sodium bicarbonate (NaHCO3) stress in irrigation water on photosynthetic characteristics and iron (Fe) and sodium (Na+) translocation content of pomegranate plants, a factorial experiment was conducted based on completely randomized design with three cultivars of pomegranate (“Gorch-e-Dadashi,” “Zagh-e-Yazdi,” and “Ghermez-e-Aliaghai”) and four concentrations of NaHCO3 (0, 5, 10, and 15 mM), with three replications. The results of plant analysis indicated that NaHCO3 affected chlorophyll index, Fv/Fm, and performance index (PI) in upper and lower leaves of shoots and also the translocation of Na+ and Fe. The results also showed that Fe translocation from root to shoot reduced at 15 mM level of NaHCO3. The highest Na translocation and the lowest Fe translocation were observed in Zagh-e-Yazdi and Ghermez-e-Aliaghai cultivars, respectively. The ratio of sodium/potassium (Na+/K+) in stems was higher than that in roots and leaves, and the observed chlorophyll content of upper leaves was also lower than that of lower leaves. Based on the measured parameters Gorch-e-Dadashi cultivar showed less relative sensitivity than other cultivars to NaHCO3 of irrigation water through maintaining the lower Na+ transport to the shoots, and improvement of Fe transport to shoots.  相似文献   

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