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1.
In this study,the 'Ganong 5th' alfalfa (Medicago sativa L.) was used as experimental material,and two application methods (leaf application,root application) and six exogenous betaine concentrations (0,10,20,30,40 and 50 mmol·L-1) were used to treat the seedlings of alfalfa. Plant growth and related physiological indexes were measured after 7 days of low temperature (4?) stress,and the physiological mechanism of exogenous betaine to alleviate the low temperature stress of alfalfa was explored. The results showed that exogenous GB alleviated the loss of plant height,root length,leaf dry weight,root dry weight and chlorophyll content,and increase the content of soluble sugar (SS) and free proline (Pro),and reduced the increase in leaf relative membrane permeability and MDA content. Exogenous GB increased antioxidant enzyme activities and non-enzymatic antioxidant content. And also,exogenous GB enhanced the osmotic adjustment capacity of the plant by increasing endogenous GB accumulation and BADH activity. These results indicated that exogenous GB enhanced the resistance of Medicago sativa to low-temperature stress under low temperature adjustment. The membership function analysis indicated that spraying 30 mmol·L-1 GB on the leaves and spraying 40 mmol·L-1 GB on the roots had the best effect on alleviating the low-temperature stress of alfalfa seedlings. © 2019 Ｊｏｕｒｎａｌ ｏｆ Ｒｅｆｒｉｇｅｒａｔｉｏｎ. All rights reserved.  相似文献   

2.
This research studied the effects of sowing date and cutting prior to sowing on establishment of the leguminous forage，alfalfa（Medicago sativa），in a lightly degraded Leymus chinensis meadow and investigated the sowing date×cutting interaction. The factorial experiment comprised four sowing dates（May 1，June 1，July 1，August 1）and cutting treatment（cut or uncut）prior to sowing，and evaluated the establishment performance of alfalfa and the ecological mechanisms related to establishment. It was found that soil moisture during emergence of alfalfa was the greatest when sowing occurred on July 1，and clipping prior to sowing significantly decreased the plant height of L. chinensis during emergence and seedling growth of alfalfa. There was a significant sowing date×cutting interaction effect on alfalfa establishment. Clipping prior to sowing significantly increased the emergence percentage of alfalfa through reducing the plant height of L. chinensis and associated above-and below-ground competition，and the seasonal soil moisture change resulted in a 20% higher（P<0. 05）alfalfa emergence rate when sowing occurred on July 1. With cutting，the number of surviving alfalfa seedlings and seedling survival rate were greatest（83 plants· m−2 and 53%，respectively）when sowing occurred on July 1. For later sowing，owing to the shortened growing time，the development and overwintering survival rates of alfalfa seedlings were significantly reduced. Cutting prior to sowing significantly increased the overwintering rate of alfalfa seedlings through improving their development. In the cutting treatment，the number of overwintered alfalfa seedlings（22 plants·m−2）when sowing was on July 1 was significantly higher than for other reseeding dates. In the second year，a botanical composition measurement showed that clipping prior to reseeding significantly increased the alfalfa biomass within the meadow，and the alfalfa biomass was significantly greater than in other treatments when sowing occurred on July 1 after cutting. Cutting prior to sowing also significantly increased the crude protein content of forage. Based on these research results，normal production practice should include cutting when alfalfa is sown into L. chinensis meadow. Combined with cutting，a sowing date around July 1 is the most favorable for the establishment of alfalfa. © 2022 Editorial Office of Acta Prataculturae Sinica. All rights reserved.  相似文献   

3.
This study firstly researched germination characteristics of Halogeton glomeratus under different concentrations of heavy metals Cu2+,Zn2+,Ni2+,Cd2+ and Pb2+ supplemented with 100 mmol·L-1 NaCl. The results showed that germination rate and germination potential increased at first and then decreased with the increase of the heavy metals concentrations. It indicated that the low concentration of heavy metal ions promoted the germination of plants. Fresh weight,dry weight and seedlings height decreased gradually. The results of ion contents showed that Cd2+ and Pb2+ contents increased at first and then decreased,and Cu2+,Zn2+ and Ni2+ contents increased with increasing heavy metals concentrations. The root activity of Cu2+ and Zn2+ increased first and then decreased,and it decreased with the increase of Ni2+,Cd2+ and Pb2+ concentrations. The comprehensive clustering and principal component analysis were carried out to obtain the critical concentrations of Cu2+,Zn2+,Ni2+,Cd2+ and Pb2+ in Halogeton glomeratus,which were 1.00 mmol·L-1,10.00 mmol·L-1,0.30 mmol·L-1,0.20 mmol·L-1 and 0.50 mmol·L-1,respectively. The most important indexes were germination index,dry weight,germination energy,dry weight and germination energy when the stress concentration reached the critical value for Halogeton glomeratus. © 2019 Ｊｏｕｒｎａｌ ｏｆ Ｒｅｆｒｉｇｅｒａｔｉｏｎ. All rights reserved.  相似文献   

4.
This research explored the effect of different levels of phosphorus application on diurnal variation in photosynthesis and partitioning of photosynthetic products in alfalfa under drip irrigation. In particular, the relationship between photosynthetic product levels in the plant and leaf photosynthetic parameters of alfalfa was clarified. Four phosphorus（P2O5）application levels of 0（CK）,50（P1）,100（P2）and 150 kg·ha-1（P3）were used as treatments in a field experiment. Leaf photosynthetic parameters were measured with a Li-6400 portable photosynthesis instrument on sunny days from 10：00-20：00 during the early flowering stage,together with environment factors and sugar and starch content in the leaves,stems and roots. A feature of the results was a ‘photosynthetic noon-break’phenomenon across all phosphorus application treatments,and stomatal limitation was the main factor responsible for the mid-day decline of net photosynthetic rate （Pn）. Photosynthetically active radiation had the greatest impact on the Pn of alfalfa leaves,while atmospheric CO2 concentration,atmospheric temperature,and atmospheric environmental factors such as relative humidity and vapor pressure deficit based on leaf temp also affected Pn. Principal component analysis showed that alfalfa photosynthetic efficiency in the four P-treatments ranked P2>P1>P3>CK. At the 100 kg·ha-1 phosphorus level（compared to CK）,the hay yield of alfalfa was increased significantly,the soluble sugar contents of leaves,stems,and roots were increased by 11. 6%,5. 0% and 4. 6%,respectively,and the starch contents were increased by 15. 2%,9. 6% and 5. 3%,respectively. Higher overall levels of soluble sugar and starch typically manifested as greater concentration increases in leaves,and relatively smaller increases in roots and stems. The diurnal troughs in Pn,transpiration rate,leaf internal CO2 concentration and water use efficiency（WUE）of alfalfa leaves were less marked in the P treatments,compared with the control treatment. Therefore,appropriate phosphorus application can increase the photosynthetic efficiency of alfalfa leaves,thereby significantly promoting crop growth and development. At the phosphorus（P2O5）application rate of 100 kg·ha-1（P2）,the alfalfa photosynthetic enhancement effect was the most pronounced. © 2022 Editorial Office of Acta Prataculturae Sinica. All rights reserved.  相似文献   

5.
The aim of this study was to compare the quality characteristics and mineral content of the fiber from male and female cashmere goats raised under different management systems. Male and female Raeini cashmere goats (<1.5 years of age, n = 48) were selected from flocks raised at a government breeding station or raised commercially under either rural or nomadic conditions. The staple length, cashmere fiber diameter, coefficient of variation for fiber diameter, percentage of cashmere in a fleece, percentage of guard hair in a fleece and cashmere tenacity averaged 4.6 ±0.1 cm, 18.0 ±0.1 m, 20.9 ± 0.4%, 66.1 ± 1.5%, 33.8 ± 1.5% and 1.8 ± 0.2 gf/tex, respectively. The sulfur, copper and zinc content of the cashmere averaged 2.8 ± 0.1%, 0.00065 ± 0.00002% and 0.01276 ± 0.00025%, respectively. Rearing method significantly affected staple length, coefficient of variation of fiber diameter, cashmere tenacity and copper content. Males had a higher coefficient of variation of fiber diameter and cashmere tenacity than females (P < 0.05).  相似文献   

6.
In order to understand the distribution and change of stable carbon isotope13C in grassland plants and the effects of soil moisture and temperature on the stable carbon isotope13 C composition (δ13 C), w e measured the δ13 C of shoots and living roots which both had two treatments, 13 C pulse labeling treatment and control treatment, and analyzed the effect of soil moisture content, air temperature and ground temperature on the δ13 C of plants body during the fast-growing stage (July-September) of the Leymus chinensis grassland in Inner Mongolia. The results showed that the δ13C of the living roots was 1-2% higher than the δ13C of the shoots in control treatments, and the δ13C of the shoots in13C pulse labeling treatment was significantly greater than the δ13C of the living roots. The variation trends of the δ13C value of shoots and living roots in labeling and control treatments were both in good consistency with time, which showed that the value of13C in shoots and living roots decreased at first, then increased, and then decreased during the growing season of plants. The δ13 C of the shoots and living roots in control group and living roots in13 C pulse labeling treatment had a linear negative correlation with soil moisture content in the layer of 0-20 cm, but the δ13C of shoots in13C pulse labeling treatment had Quadratic function relation with the soil moisture content in the layer of 0-20 cm, which indicated that the δ13C increased with increasing soil moisture content when it had a low soil moisture content, and the δ13C decreased when there was a high soil moisture content. In13 C pulse labeling treatment and control treatment, there were significant positive correlation between temperature and the δ13C of the shoots and living roots, the δ13C of the shoots and living roots increased with increasing the temperature. © 2019 China Agricultural University. All rights reserved.  相似文献   

7.
This research explored the physiological and ecological responses and secondary metabolites of Thlaspi arvense （pennycress） under salt stress in order to develop a theoretical foundation for further research on the planting of salt-tolerant plants on saline-alkali soils. Hydroponically cultured pennycress was grown at 5 NaCl concentrations （0,50,100,150,200 mmol·L−1） set to simulate a gradient of salt stress intensity. Leaves of pennycress were collected at 1,5,10,and 15 days to determine physiological and biochemical indexes,photosynthetic parameters and secondary metabolite levels. It was found that： 1） The activities of superoxide dismutase,peroxidase,and catalase in the leaves of T. arvense showed a pattern of initial increase and then decrease with increase in salt concentration during the period of salt stress. 2） The enzyme activity was highest at the NaCl concentration of 100 mmol·L−1. 3） Levels of malondialdehyde first increased and then decreased with increase in salt concentration. 4） The contents of soluble sugar and proline in the leaves of T. arvense increased with increase in salt concentration and with the length of exposure to NaCl stress,while soluble protein levels first increased and then decreased with increase in salt concentration. 5） The chlorophyll a, chlorophyll b, total chlorophyll content, chlorophyll fluorescence parameters,net photosynthetic rate and transpiration rates in T. arvense leaves showed a downward trend with increase in salt concentration,and the decline gradually increased. 6） The contents of total flavonoids,total phenols,and sinigrin in the leaves of T. arvense showed a pattern of initial increase and then decreasing with increase in salt concentration. Thus,pennycress has a high tolerance to salt stress and can maintain normal growth in a salt-stress environment of 50-100 mmol·L−1 NaCl concentration. This result provides a theoretical basis for future research on the salt tolerance mechanisms of T. arvense and other natrophilic plants. © 2022 Editorial Office of Acta Prataculturae Sinica. All rights reserved.  相似文献   

8.
Background: Flight is the central avian adaptation in evolution. Wing muscles form an important anatomical basis for avian flight, affecting wing performance and determine modes of flight. However, the roles of distal muscles in adjusting the wing, as well as their functional specializations, remain largely unknown. The importance of muscle fiber architecture has long been recognized. In this study, we provide quantitative anatomical data on the muscle architecture of the forelimb of the Golden Pheasant(Chrysolophus pictus), with an emphasis on brachial,antebrachial and manual segments.Methods: The forelimbs of five Golden Pheasants were dissected and detailed measurements of all muscles were made, including muscle mass, muscle belly length, fascicle length. From these values, muscle volume, physiological cross-sectional area(PCSA) and maximum isometric force were derived.Results: General trends such as the distribution of muscle mass, fascicle length and the ratio of tendon length/belly length are revealed. Comparing PCSAs between antebrachial depressors and elevators and between intrinsics of the alular digit and major digit yielded significant differences(p < 0.05). Pronounced development of the antebrachial depressors suggests that ventral rotation of the distal half of the wing is a pivotal factor in shape change and orientation modulation. Large PCSAs in tandem with the force generation capability of the major digit intrinsics may help stabilize the digits while enhancing support of the primary feathers. The architectural properties of the alular digit confirm that alular adjustment is essential to rapid adduction and abduction.Conclusions: These observations illustrate the underlying structural basis for the functional capacities of the distal forelimb muscles and may provide additional information useful in further biomechanical and in vivo investigations.  相似文献   

9.
Eighteen (Duroc × Landrace × Yorkshire) castrated boars,55 days of age and weighing approximately 19 kg,were used to investigate the effects of montmorillonite nanocomposite on tissue levels of lead as well as changes in blood biochemical parameters in pigs fed lead contaminated diets.The barrows were randomly assigned to one of three treatments (n=6) including a control which were fed a basal diet based on corn and soybean meal.The remaining two groups were fed the basal diet supplemented with 10 mg/kg lead either with or without 0.5% montmorillonite nanocomposite for 50 days.Pigs treated with lead had significantly increased levels of lead in their tissues.Lead accumulated in all tissues of the body with the highest accumulation found in the hair.When montmorillonite nanocomposite was given along with lead,tissue concentrations of lead did not differ from the control.Fecal excretion of lead increased significantly in lead-exposed pigs treated with montmorillonite nanocomposite.A progressive and appreciable accumulation of lead was seen in blood with a concomitant increase in zinc protoporphyrin levels during the course of treatment.However,zinc protoporphyrin levels did not differ from the control when montmorillonite nanocomposite was administered along with lead.The activity of δ-amino levulinic acid dehydratase in blood was significantly increased in lead treated pigs compared with the control.However,in pigs treated with lead and montmorillonite nanocomposite in combination,the activity of δ-amino levulinic acid dehydratase was similar to control pigs.Our results indicate that montmorillonite nanocomposite treatment of pigs exposed to lead resulted in reduced lead concentrations in body tissues.It appears that montmorillonite nanocomposite functions by increasing fecal excretion of lead.  相似文献   

10.
Four crossbred （Duroc x Landrace x Yorkshire） boars, weighing an average of 22.40 ± 1.08 kg and fitted with permanent catheters in their portal and mesenteric veins as well as their carotid artery,were utilized in a 4 × 4 latin square design experiment in order to investigate the effects of different starch sources （maize ,brown rice, sticky rice, and resistant starch） on the absorption of energy sources through the portal vein. Portal blood flow averaged 30.68, 28.40, 29.99, and 30. 12 mL/min per kg BW for pigs fed the maize, brown rice, sticky rice, and resistant starch diets, respectively, and did not dif- fer （P 〉 0.05） between treatments. The absorptions of glucose, plasma ammonia, and total amino acids were significantly lower （P 〈 0.05 ） in pigs fed the resistant starch diet than pigs fed the other starch sources. In contrast, significantly （ P 〈 0.05 ） higher amounts of propionate and total volatile fatty acids were absorbed from the portal vein of pigs fed resistant starch than pigs fed diets based on maize, brown rice, or sticky rice. In addition, significantly （P 〈 0.05） more lactic acid was absorbed from the portal vein by pigs fed the sticky rice diet than pigs fed the other three diets. The energy absorbed from the portal vein in the form of glucose and amino-N as well as the total energy absorbed was significantly （P 〈 0.05） lower in pigs fed the resistant starch diet than pigs fed the other three starch sources. In contrast, the amount of energy absorbed in the form of volatile fatty acids was significantly （P 〈 0.05 ） higher in pigs fed resistance starch than pigs fed the other three starch sources. The total energy absorbed through the portal vein as a percentage of the gross energy and digestible energy consumed in pigs fed maize were 50.8% and 54.6%, respectively, which were significantly （P 〈 0.05 ） higher than the values in pigs fed resistant starch （41.5% and 46.6% respectively）. The results indicate that energy is absorbed in different forms and with different utilization efficiencies in the digestive tract of pigs as a result of feeding different starch sources. Starch sources supplying most of their energy in the form of glucose had higher energy utilization efficiencies, while starch sources supplying most of their energy in the form of volatile fatty acids or lactic acid had lower energy utilization efficiencies.  相似文献   

11.
为探究镉（Cd）胁迫条件下，施硅（Si）对玉米幼苗生长以及根系构型分级的影响，寻求可缓解Cd对玉米毒害的有效途径，本研究采用水培试验，在Cd胁迫条件下施加不同浓度Si，测定玉米的Cd浓度及含量、生长相关指标、光合指标、根系构型，并将根系构型按根系直径进行分级比较其变化特征。结果表明，Cd胁迫条件下玉米幼苗的生长发育受到抑制，叶绿素含量上升，光合参数显著降低，总根长、根表面积、根体积、根尖数和分枝数，包括Ⅰ~Ⅲ级径级区间的根长，和Ⅰ~Ⅱ级径级区间的根表面积以及根体积显著下降。施加不同浓度Si后，玉米幼苗整株Cd含量降低了12.65%~88.07%，Cd毒害在不同程度上得到缓解，表现为株高、主根长、生物量和耐受指数的提高；总叶绿素含量在Si浓度为0.25 mmol·L-1时提高了11.76%，Cd胁迫下气孔导度、胞间CO2浓度和蒸腾速率分别在Si浓度为1.00 mmol·L-1时显著提高；总根长、分枝数、Ⅰ级径级区间的根长、根表面积和根体积在Si浓度为1.00 mmol·L-1时达到最大，当Si浓度为1.50 mmol·L-1时，根表面积和根体积达到峰值。相关性分析表明Ⅰ~Ⅲ级径级区间内的总根长和根表面积，以及Ⅰ~Ⅱ级径级区间的根体积与Cd转运系数呈显著负相关；生长耐受性综合评价表明，总体上1.00 mmol·L-1外源Si缓解50 μmol·L-1玉米Cd毒害的效果最佳。结果表明，施Si可通过降低玉米幼苗根系对Cd的吸收、积累和转运，减少地上部的Cd浓度及积累，从而减小Cd对光合系统的影响，提高玉米幼苗生物量，并进一步促进光合产物向地下部的分配，减轻Cd对根系构型的影响，提高玉米耐Cd能力，缓解Cd对玉米的毒害作用。  相似文献   

12.
为评价红三叶种质耐铜能力强弱,筛选出优异种质材料,以30份国内外红三叶材料为对象,研究其萌发期和幼苗生长阶段Cu2+胁迫下的生长发育特性,并采用隶属函数法对红三叶耐铜性进行综合评价。结果表明：随着Cu2+胁迫浓度的增加,红三叶发芽率逐渐降低,胚根变短,变粗;胚根在Cu2+浓度为0.5 mmol·L-1下长度为对照的40%~69%,在Cu2+浓度为8.0 mmol·L-1时停止生长,而发芽率在Cu2+浓度为8.0 mmol·L-1时为对照的61%~93%,相对于发芽率,胚根对Cu2+胁迫更为敏感。红三叶幼苗能够耐受20 mmol·L-1的Cu2+胁迫,但其地上生物量、地下生物量、根总长度、根尖数以及根体积均显著降低。不同浓度间红三叶各性状差异显著（P<0.05）,且萌发期（0.5 mmol·L-1）和苗期（20 mmol·L-1）不同红三叶材料间同一性状亦存在显著差异性（P<0.05）;胚根长度与胚根直径、地上生物量与地下生物量、地下生物量与根冠比、根总长度和根尖数等性状之间具有显著相关性（P<0.01）;依据最小二乘法原理,建立了以胚根长度、幼苗存活率、地下生物量和根总长度4个关键指标为因子的预测模型,其预测值与综合评价值显著相关（R2=0.977）。综合评价结果表明,材料CF022167、CF022178及CF022232具有较高的铜胁迫耐受性,可作为红三叶耐铜性新品种选育的基础材料或在生产中直接利用。  相似文献   

13.
苜蓿根系构型及生理特性对干旱复水的响应   总被引：1，自引：0，他引：1  
为了研究苜蓿根系构型及生理特性对干旱复水后的响应,对肇东苜蓿进行盆栽控水试验。设置正常供水（CK）、轻度干旱（LS）、中度干旱（MS）和重度干旱（SS） 4个处理,在干旱处理4周后进行复水,研究各处理间根系构型及生理指标的差异。结果表明：干旱处理对根干重和根尖数有极显著影响（P<0.01）,对比根长、根表面积、根体积和根密度有显著影响（P<0.05）。干旱胁迫抑制了根系的生长,降低了根干重、根长、根表面积、根体积、根密度和根尖数等形态指标,促进了比根长的增加。各处理间拓扑指数差异显著（P<0.05）,干旱促进苜蓿根系从二分枝型向人字形结构转变。干旱胁迫极显著（P<0.01）增加了根系丙二醛（MDA）和超氧负离子（O2-）的含量,同时超氧化物歧化酶（SOD）活性和谷胱甘肽（GSH）含量也极显著增加（P<0.01）,从而保持体内活性氧处于较低水平。脱落酸（ABA）含量在干旱胁迫下极显著（P<0.01）增加,通过其生理作用及信号传导途径提高苜蓿抗旱性。  相似文献   

14.
筛选适宜黑龙江省西部地区种植的苜蓿品种,探究苜蓿越冬率与根系性状及产量之间的相关性,为建立苜蓿人工草地提供优良品种。以国内外8个不同秋眠等级苜蓿品种为材料,采用随机区组设计,测定苜蓿产量、越冬率和根系性状(根颈直径、体积、入土深度、根长、主根直径、根尖数量、侧根直径、侧根位置、侧根数量、根系生物量)指标,通过主成分分析和隶属函数评价筛选出最佳品种。公农2号、草原3号和肇东苜蓿的越冬率均大于95%,越冬率与根系生物量呈显著负相关(P<0.05),相关系数为0.762;越冬率与根颈直径、入土深度呈显著正相关(P<0.05),相关系数分别为0.797和0.756,与侧根位置呈显著负相关(0.712;P<0.05)。越冬率与产量呈极显著正相关(0.956;P<0.01),其中肇东苜蓿、草原3号和公农2号产量较高,分别为12746.73、11921.24、11416.77 kg·hm-2,显著高于其他品种(P<0.05)。经主成分分析选出根颈直径、体积、入土深度、根长、主根直径、侧根直径、侧根数量和越冬率作为鉴定苜蓿耐寒性的重要指标,应用隶属函...  相似文献   

15.
以光叉委陵菜的多年生植株作为试验材料,通过自然控水法,研究不同干旱处理对植株根系的表型特征、超微结构和生理指标的影响,探究光叉委陵菜的耐旱性。结果表明:干旱胁迫下,光叉委陵菜根系总长度、总表面积、总体积和平均直径持续增加,根系干重在0~15 d增加,20~25 d干重显著降低(P<0.05)。随干旱胁迫程度的增加,根系细胞壁变形破损,线粒体解体消失,淀粉粒出现并不断膨大。丙二醛(MDA)含量、脯氨酸含量在25 d内持续升高,可溶性蛋白含量、超氧化物歧化酶(SOD)活性在0~15 d显著升高,在20~25 d均显著下降(P<0.05);复水后,脯氨酸含量下降但不显著(P>0.05),MDA含量、可溶性蛋白含量、SOD活性均出现显著降低(P<0.05)。综合来看,光叉委陵菜能耐20 d的自然干旱,具有较强的抗旱性,这为东北地区选育耐旱植物提供了参考。  相似文献   

16.
为研究紫花苜蓿在叶片和根系水平上响应干旱胁迫的形态和生理的品种特异性规律,在温室内分析了干旱胁迫下WL363HQ和巨能7紫花苜蓿株高、分枝数、生物量及叶片和根系中丙二醛（MDA）、脯氨酸、抗氧化酶类物质、C、N含量、C/N、稳定性C同位素（δ13C）和稳定性N同位素（δ15N）。结果表明：干旱胁迫显著降低了供试品种地上部分和根系的干重及分枝数（P<0.05）。干旱胁迫显著降低了巨能7的株高（P<0.05）,但增加了巨能7的根冠比,而WL363HQ的结果与之相反,这说明干旱胁迫下供试品种的株高和根冠比具有品种特异性的规律。干旱胁迫增加了WL363HQ和巨能7叶片和根系中MDA和脯氨酸的含量及抗氧化酶物质的活性,且在器官水平也具有品种特异性规律。干旱胁迫下巨能7叶片的MDA含量显著增加（P<0.05）,而在WL363HQ根系中的MDA含量也显著增加（P<0.05）。干旱胁迫下WL363HQ叶片脯氨酸含量、POD和SOD活性,及根系SOD的活性均显著增加（P<0.05）,而巨能7仅叶片SOD活性,根系脯氨酸含量、POD活性显著升高（P<0.05）。尽管干旱胁迫对供试品种叶片和根系C、N含量无显著影响（P>0.05）,但干旱胁迫显著提高了WL363HQ和巨能7紫花苜蓿根系的δ13C（P<0.05）,且WL363HQ叶片的δ15N均显著高于巨能7（P<0.05）。此外,干旱胁迫均显著提高了巨能7叶片和根系的C/N（P<0.05）。干旱胁迫下供试品种C、N代谢参数并没有在叶片和根系中表现出较为明显的品种特异性规律,深层次的机制还有待进一步研究。本研究结果将为进一步掌握紫花苜蓿叶片和根系协同抗旱机制及抗旱丰产紫花苜蓿新品种的选育提供理论依据。  相似文献   

17.
杨林  陈默  李海燕  杨允菲 《草业学报》2021,30(1):181-188
作为全球气候变化的重要组成部分,降雨格局变化能够对各类植物产生不同的影响。虎尾草为退化盐碱草地恢复的主要先锋种植物之一,降雨格局变化如何影响其分株和根系等特征对于全球变化背景下退化盐碱地的生态恢复至关重要。本研究通过人工模拟降雨格局变化试验,设置了3个降水量（减少30%、不变、增加30%）和2个降雨间隔（1、2 d）, 研究了虎尾草地上分株和地下根系形态特征对降雨格局变化的响应。结果表明：1） 降雨格局的变化对虎尾草有性生殖特征几乎无影响,随着降水量增加或降雨间隔延长营养繁殖特征具有增加的趋势。2） 降雨间隔和降水量对虎尾草根系影响程度不同,降雨间隔为主要影响因素,且二者相互依赖。降水量一定时,随着降雨间隔的增加,总根长、总表面积、总体积和根直径显著降低。3） 降水量和降雨间隔均影响虎尾草生物量的积累,降雨间隔为主要影响因素,随着降雨间隔的增加,根、茎、总生物量均显著降低,叶和花序生物量具有减小的趋势,但是影响不显著。  相似文献   

18.
为探讨不同氮磷配施条件下紫花苜蓿细根周转及不同土层分布动态特征,分析苜蓿细根周转各指标之间的关系。采用双因素随机区组设计进行田间试验,设置4个施磷水平［0（P0）、50（P1）、100（P2）和150 kg·hm-2（P3）］和两个氮水平［0（N0）和120 kg·hm-2（N1）］,共计8个处理,通过微根管根系监测0~60 cm的土层细根周转特征。结果表明：在相同施氮条件下,随着施磷量的增加,紫花苜蓿细根总现存量、细根表面积密度、细根生产量和死亡量呈先增加后降低的趋势,在P2条件下达到最大值,且P1、P2处理显著大于P0处理（P<0.05）,在相同施磷条件下,N1处理显著大于N0处理。在不同土层中,在相同施氮条件下,随着施磷量的增加,苜蓿细根现存量在0~30 cm土层中呈先增加后降低的趋势,在0~15 cm土层中,P2处理苜蓿细根现存量显著高于其他处理（P<0.05）。不同处理下,苜蓿细根现存量主要集中在15~30 cm土层。在相同施氮条件下,随施磷量的增加,苜蓿细根周转率呈先降低后增加的趋势。细根周转率受细根现存量与细根死亡动态变化的影响较大。细根死亡量与周转率拟合的相关系数最大,拟合效果最好。综上所述,当施磷（P2O5）量为100 kg·hm-2、施氮（N）量为120 kg·hm-2时,能够显著增加苜蓿细根的现存量和根表面积密度,进而促进苜蓿根系周转和生长。  相似文献   

19.
蔡文涌  王肖肖  方香玲 《草地学报》2020,28(5):1233-1239
利用从甘肃省3个不同地区紫花苜蓿（Medicago sativa）根腐病植株分离纯化的尖孢镰刀菌（Fusarium oxysporum）菌株,研究了不同菌株对苜蓿幼苗生长的影响。通过不同菌株米粒接种体接种土壤后移栽苜蓿幼苗,28 d后对植株的根部病害进行分级,对株高、根长、地上生物量和地下生物量进行测定。结果表明,不同菌株对苜蓿幼苗根部病害的严重程度和生长有显著影响（P<0.05）,致病力强弱存在差异。接种不同菌株后,幼苗根病情指数为46%~69%;根长和株高分别降低9%~28%和20%~52%;地上生物量和地下生物量分别降低17%~48%和15%~60%。其中,菌株QY3致病力最强,其次为QY2,菌株LZ3致病力最弱;菌株QY2导致根长和地上生物量的降低幅度最大;菌株LT2导致株高和地下生物量的降低幅度最大。研究结果为苜蓿根腐病的防治提供了初步的理论指导。  相似文献   

20.
以内蒙古草甸草原、典型草原、荒漠草原3种草原实验区草地植物群落为研究对象, 设置7种氮添加梯度, 分别为CK（0 g N·m-2·a-1）、N1（5 g N·m-2·a-1）、N2（10 g N·m-2·a-1）、N3（15 g N·m-2·a-1）、N4（20 g N·m-2·a-1）、N5（25 g N·m-2·a-1）、N6（30 g N·m-2·a-1）,应用单因素方差分析（One-way ANOVA）方法研究不同浓度梯度氮添加下不同草原类型区植被生物量、土壤碳氮差异及其影响因素。结果表明：1）氮添加并未对3种草原类型地下生物量产生显著影响（P>0.05）,但显著提高了草甸草原和荒漠草原地上生物量（P<0.05）,且本研究初步判断在N3添加时接近饱和阈值, 整体上氮添加使内蒙古草原总生物量平均增加了29.66%,较干旱的荒漠草原对氮添加的响应较为明显。施氮肥使草甸草原的根冠比显著降低（P<0.05）,典型草原根冠比在N3处理下显著增加（P<0.05）,但对荒漠草原影响不显著（P>0.05）。2）选择不同土层（0~10 cm、10~30 cm）分析氮添加对3种草地类型土壤有机碳、全氮含量的影响, 结果显示氮添加对草甸草原土壤碳氮含量没有显著影响（P>0.05）,对典型草原和荒漠草原土壤碳氮含量存在显著影响（P<0.05）,且0~10 cm土层对施氮的响应更明显。3）施氮条件下地上生物量与土壤C/N、年均降水显著相关（P<0.01）,地下生物量、总生物量均与土壤全氮含量、有机碳含量、土壤C/N、年均温、年均降水显著相关（P<0.01）。总的来说,不同类型的草地生态系统生物量及土壤碳氮含量对施肥的响应存在差异,这意味着草地恢复与管理过程中需要对养分的添加作用进行考虑。  相似文献   

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