共查询到20条相似文献，搜索用时 70 毫秒
1.
《中国草地学报》2017,(1)
以9∶1摩尔比的NaHCO_3和Na_2CO_3混合液模拟典型碱胁迫环境,在0mmol/L、25mmol/L、50mmol/L和100mmol/L 4个碱处理梯度下,采用硅胶干燥法将垂穗披碱草种子水分分别从8.20%(CK,未处理)降低到5.33%、4.67%、4.17%和4.07%,研究碱胁迫对超干处理下不同水分含量垂穗披碱草种子萌发及幼苗生长的影响。结果表明:相同水分含量的种子,随着胁迫浓度增加,发芽率、发芽势、发芽指数、株高和幼苗活力指数均呈不同程度降低趋势,而相对危害率、脯氨酸及丙二醛含量呈增加趋势;在相同碱液胁迫下,不同水分含量种子的以上指标变化规律不尽相同。采用平均隶属度法进行综合评价,不同碱液处理下不同含水量种子平均隶属度排序为4.67%8.20%(CK)4.07%5.33%4.17%;超干处理不同含水量种子,其不同碱液浓度平均隶属度值25mmol/L0mmol/L(CK)50mmol/L100mmol/L。综合评价结果表明,垂穗披碱草种子在含水量为4.67%、碱液浓度为25mmol/L时明显促进种子萌发及幼苗生长。 相似文献
2.
3.
为了研究垂穗披碱草修复铜(Cu)、锌(Zn)和锰(Mn)污染土壤的能力,试验以采自西藏3个不同地区野生垂穗披碱草种子(01号、02号、03号)为试验材料,采用人工模拟Cu~(2+)、Zn~(2+)及Mn~(2+)胁迫的方法初步探究了Cu~(2+)、Zn~(2+)、Mn~(2+)胁迫对垂穗披碱草种子萌发、幼苗生长和幼苗中丙二醛(MDA)含量的影响,并采用隶属函数法进行了重金属抗性评价。结果表明:Cu~(2+)胁迫对垂穗披碱草种子的发芽率、发芽势、根长、株高、根重、芽重具有抑制作用,Zn~(2+)和Mn~(2+)胁迫对垂穗披碱草种子的萌发指数及幼苗生长指数的影响均表现为"低促高抑"的规律;3种垂穗披碱草幼苗中MDA含量随金属离子浓度的升高表现出上升的趋势;重金属抗性评价显示,01号垂穗披碱草对3种金属的耐性较高,可驯化育种,可为重金属污染土壤的修复提供良好的种质资源。 相似文献
4.
为明确外源2,4-表油菜素内酯(24-epibrassinolide,EBR)对盐胁迫下紫花苜蓿幼苗伤害的缓解作用,以中苜3号和陇中苜蓿为材料,在150mmol/L NaCl胁迫下,研究不同浓度EBR处理对紫花苜蓿种子萌发及幼苗生长的影响。结果表明:(1)150mmol/L NaCl胁迫显著抑制了苜蓿种子萌发、幼苗生长及根系活力,降低了幼苗的地上、地下生物量;(2)外源EBR可有效的缓解NaCl胁迫对苜蓿种子萌发、幼苗生长及根系活力的抑制作用,并具有明显的浓度效应;(3)综合发芽试验、幼苗生长试验,在150mmol/L NaCl胁迫下,10-1μmol/L EBR处理显著地提高了苜蓿种子的发芽势、发芽率、发芽指数、活力指数和胚芽长、胚根长、萌发期幼苗干重,并显著增加了苜蓿幼苗的叶片数、茎粗、株高、主根长、侧根数和地上、地下生物量,提高了苜蓿萌发期、幼苗期的根系活力水平,对盐胁迫下苜蓿幼苗的缓解效果最好。说明外源EBR能够促进NaCl胁迫下紫花苜蓿种子的萌发及幼苗的生长发育,EBR在诱导植物抗盐性上具有积极作用。 相似文献
5.
研究了西藏巴青县野生垂穗披碱草种子萌发与幼苗生长对重金属Mn2+、Pb2+胁迫的生理响应机制,为西藏矿区周边污染土壤和植被修复提供依据。选取西藏巴青县野生垂穗披碱草为试验材料,采用纸上发芽法研究了重金属Mn2+、Pb2+对其种子萌发和幼苗生长的影响。结果表明,Mn2+、Pb2+离子胁迫对垂穗披碱草种子萌发和幼苗生长具有极显著的影响(P<0.01);随着Mn2+、Pb2+浓度的增大,垂穗披碱草种子发芽率、发芽势、发芽指数、活力指数及胚芽长表现为下降的趋势;在200 mg·L-1 Mn2+、Pb2+溶液浓度培养下垂穗披碱草种子根较对照略长;随着Mn2+、Pb2+溶液浓度的升高,垂穗披碱草幼苗叶片叶绿素a和叶绿素b含量持续降低而电导率和MDA含量呈上升趋势。垂穗披碱草对Mn2+、Pb2+具有一定的耐受性,可适用于Mn2+、Pb2+轻度污染土壤。 相似文献
6.
本研究探索了西藏巴青县野生垂穗披碱草(Elymus nutans)种群繁殖扩散机理,为其开发利用提供必要的理论基础。试验在不同光、温、水(PEG6000)、盐处理条件下研究了垂穗披碱草种子萌发特性。结果表明:光照对垂穗披碱草种子萌发无显著影响;恒温25℃和变温20/30℃条件下垂穗披碱草种子萌发速度较快、发芽率较高,而5℃和35℃条件下种子不萌发;在PEG浓度为5%时垂穗披碱草种子发芽率略高于对照(CK),但其发芽指数和活力指数都显著低于对照(CK);在Na Cl溶液浓度为0%~0.4%范围内,种子均能正常萌发,且轻度盐胁迫(0.2%)对垂穗披碱草种子萌发有促进作用。上述结果说明,低温是限制西藏巴青地区野生垂穗披碱草种子成功萌发的关键因子。 相似文献
7.
为了筛选基于MS培养基的盐节木种子萌发与幼苗生长的最佳NaCl浓度,及初步探讨NaCl渗透胁迫作用(使用MS盐消除了NaCl的离子毒害作用)促进根生长的机制, 以MS为基本培养基研究了不同浓度的NaCl(0~700 mmol/L)对贮存7年的盐节木种子在三角瓶中萌发及幼苗生长的影响,并用光学显微镜对适宜盐浓度促进盐节木根伸长的初步机制进行了根尖形态与细胞学观察。结果表明, 1)储藏7年的种子仍有活力,对照组的活力指数和萌发率分别为3.36和74.46%,但萌发时间与前人比较有所延迟。2)盐节木种子的萌发具有不同步性,初始萌发天数为6~8 d,萌发可持续到25~30 d。3)基于 MS培养基盐节木种子萌发最佳浓度为100~200 mmol/L,与对照比可使萌发时间提早2 d,且盐害率为负值。4)幼苗生长适宜的NaCl浓度范围为100~300 mmol/L,最佳浓度为200 mmol/L;盐对幼苗表型的影响是MS0和NaCl>300 mmol/L的MS培养基中生长的幼苗在1个月内能促进多数幼苗下胚轴变红,3~4个月后多数幼苗同化枝变红,而附加100~200 mmol/L NaCl的培养基植株大多数呈绿色。5)根尖细胞学观察可知:MS附加100和200 mmol/L NaCl促进根生长的原因是:NaCl促进了根尖分生组织细胞的分裂和伸长区与成熟区细胞的伸长,因而加速了根冠细胞的程序性细胞死亡,表现为根冠细胞脱落加快。本研究为盐节木耐盐机理的继续深入研究打下了一定的基础。 相似文献
8.
硅对NaCl胁迫下甜瓜种子萌发及幼苗生长的影响 总被引：1，自引：0，他引：1
为明确硅(silicon,Si)对盐胁迫的缓解作用,以“雪梨一号”和“朗秦银蜜”两个耐盐性不同的甜瓜品种为材料,在125 mmol/L NaCl胁迫下,研究了不同浓度外源Si对甜瓜种子萌发和幼苗生长的影响。结果表明,NaCl胁迫显著抑制了甜瓜种子萌发,0.50~1.00 mmol/L外源Si处理较对照能显著提高种子的发芽率、发芽势、发芽指数、α-淀粉酶活性及吸水率,其中两个品种的种子均以0.75 mmol/L外源Si处理效果最好;NaCl胁迫下,0.25~1.00 mmol/L外源Si处理后,甜瓜幼苗的株高、叶面积、叶绿素含量、地上部分干重和根系干重较对照显著提高,其中“朗秦银蜜”和“雪梨一号”幼苗分别以0.50和0.75 mmol/L外源Si处理效果最好。研究表明,0.25~1.00 mmol/L外源Si能促进NaCl胁迫下种子吸水和α-淀粉酶活性的提高来促进种子萌发,通过提高NaCl胁迫下幼苗叶绿素含量维持较高的光合能力促进幼苗生长,缓解盐胁迫对甜瓜种子和幼苗的伤害,外源Si浓度超过1.25 mmol/L时对盐胁迫没有缓解效应。 相似文献
9.
盐胁迫对桑种子发芽及幼苗生理生化特性的影响 总被引：9，自引：1，他引：8
桑树在盐碱地栽培 ,受盐害最为严重的时期是种子萌发及幼苗期。采用不同浓度的NaCl溶液胁迫桑种子 ,研究高盐逆境条件下对种子发芽、幼苗生长及生理效应的影响。结果表明 :随NaCl浓度增大 ,桑种子的萌发率、发芽率逐渐下降 ,发芽滞后且发芽后的幼苗生长被抑制 ,当NaCl的浓度达到 5 0mmol/L时 ,子叶长出率、幼苗鲜质量明显下降 ,在 15 0mmol/L浓度下种子无法长出子叶 ;各处理区叶片的含水率、叶绿素的含量也随NaCl的浓度升高而下降 ;脯氨酸含量则随NaCl浓度增大呈先升高后降低的趋势。 相似文献
10.
采用水培的方法,以采自西藏高寒区域不同地区的野生垂穗披碱草种子为材料,初步探讨了酸性环境下(pH 4.5)不同浓度的Al3+(0、0.5、1.0和1.5 mmol·L-1)胁迫对垂穗披碱草种子萌发及幼苗生长的影响,以期为酸铝土壤的改良提供优良的种质资源。研究结果显示,低浓度Al3+(0.5、1.0 mmol·L-1)对3种垂穗披碱草种子的发芽率无显著影响(P>0.05),但Al3+浓度为1.5 mmol·L-1时,3种垂穗披碱草种子的发芽率均被显著抑制(P<0.05)。同时,3种野生牧草的根长、株高、根重及茎叶重在Al3+胁迫下受到了不同程度的抑制,且根系被抑制的程度大于茎叶。此外,植物幼苗中丙二醛和可溶性糖作为受胁迫程度的重要指标,其含量在3种垂穗披碱草幼苗中均随Al3+浓度的升高呈现出上升的趋势。结果还表明,1.5 mmol·L-1 Al3+处理时,那曲、申扎、浪卡子垂穗披碱草根系中铝含量分别是地上部的12.2、15.3、17.5倍。铝毒和磷缺失往往是酸性土壤中同时存在的问题,这严重影响了植物生长,研究表明Al3+抑制了垂穗披碱草对磷的吸收及转运。通过隶属函数法对3种垂穗披碱草的抗铝特性评估结果显示,采自申扎县的垂穗披碱草对Al3+的耐性较高,可驯化育种,为酸性土壤的改良提供优质的种质资源。 相似文献
11.
12.
13.
魏静 《四川畜牧兽医学院学报》2009,(4):28-32
在现代法律秩序中,商会自治规范是制定法的基础和必要的补充,甚至在某些方面替代了制定法;商会自治规范主要包括商会组织规范、行为规范、惩罚规范以及争端解决规范等;其效力仅及于其内部成员;商会自治规范和制定法之间存在冲突,但也存在整合的基础。 相似文献
14.
本文概述了猪的毛色类型、猪的毛色遗传模式,着重综述了猪毛色基因分子基础的研究进展,指出存在问题并就未来发展方向做了思考。 相似文献
15.
16.
以国际标准强毒Ｒ株人工感染非免疫产蛋鸡,定时扑杀,分别从鼻窦、眶下孔、气管、肺、气囊、卵巢和输卵管分离ＭＧ,并收集感染鸡所产蛋分离ＭＧ。结果表明,人工感染４８小时后上、下呼吸道及肺已被全面感染,９６小时气囊已被感染,１２０小时输卵管已能分离到ＭＧ,卵巢始终分离不到ＭＧ。人工感染鸡自１４４小时便能在其所产蛋中分离出ＭＧ。药物治疗能在７２小时内消除感染,油乳剂苗则需２４天后逐渐降低蛋内ＭＧ分离率,药物卵内注射、种蛋药浴、高温处理均能杀死卵内ＭＧ,但以研制的种蛋浸泡剂药浴效果为最好。 相似文献
17.
REASONS FOR PERFORMING STUDY: Centesis of the bicipital bursa using an 8.9 cm long spinal needle has been reported but the alternative of employing a 3.8 cm long hypodermic needle requires validation. OBJECTIVE: To compare the efficacy of 2 different methods of centesis of the bicipital bursa and to evaluate the usefulness of ultrasonographic imaging to determine the location of solution administered when centesis of the bursa is attempted. METHODS: For Trial 1, 6 clinicians, who had no previous experience of centesis of the bicipital bursa, attempted to inject a solution composed of an aqueous radiopaque contrast medium and physiological saline solution (PSS) into the bicipital bursae of 2/12 horses using the previously described distal approach to inject one bursa and a proximal approach to inject the contralateral bursa. The bicipital tendon and bursa were examined ultrasonographically before and after injection; and both shoulders were examined radiographically to identify the location of the medium. In Trial 2, another 6 clinicians, also with no previous experience of centesis, repeated Trial 1, using 6 horses, but the radiopaque contrast medium was mixed with air instead of PSS. RESULTS: Accuracy of centesis using the proximal approach was 39% and that of the distal approach 28%. Ultrasonographic examination of the shoulder allowed the location of solution and air to be accurately predicted in all 12 shoulders examined. CONCLUSIONS: Clinicians who have had no previous experience performing centesis of the bicipital bursa are unlikely to be successful in centesis using either approach. Radiographic examination after injecting a radiopaque contrast medium may be necessary to assess the success of centesis especially if bursal fluid is not obtained during centesis. Injecting air along with the radiopaque contrast medium provides more accurate ultrasonographic confirmation of centesis and better radiographic definition than does injection without air. 相似文献
18.
19.
20.
Effects of size of ingestively masticated fragments of plant tissues on kinetics of digestion of NDF
Ingestively masticated fragments were collected and sized via sieving. Different sizes of esophageal masticate and ruminal digesta fragments, and ground fragments of larger masticated pieces were incubated in vitro, and undigested NDF remaining at intervals of up to 168 h of incubation was determined. The ruminal age-dependent time delay (tau) for onset of digestion of NDF was positively correlated (P < 0.004) with the mean sieve aperture estimated to retain 50% of the fragments between successive sieve apertures (MRA). Degradation rate of potentially degradable NDF (PDF) and level of indigestible NDF were not related (P > 0.10) to MRA of masticated and ground fragments. Estimates of tau were positively related to MRA, with slopes of bermudagrass < corn silage < ruminal fragments of corn silage. It was concluded that fragment size-, and consequently, ruminal age-dependent onset of PDF degradation of a mixture of different fragment sizes results in an age-dependent rate of degradation of the more rapidly degrading of two subentities of PDF. Models are proposed that assume a tau before onset of simultaneous degradation of PDF from two pools characterized as having gamma-modeled age-dependency and age-constant rates. The ruminal age-dependent pool seems to be associated with the faster-degrading pool, and its rate parameter increases with range in MRA in the population of fragments. Conceptually, the ruminal age-dependent rate parameter for PDF degradation seems to represent a composite of several effects: 1) effects of the size-dependent tau; 2) range in MRA of the population of ingestively masticated fragments; and 3) subentities of PDF that degrade via more rapid age-dependent rates compared with subentities of PDF that degrade via age-constant rates. The estimated fractional rates of ruminative comminution of ingestively masticated fragments (0.060 to 0.075/h) were of a magnitude similar to the mean fractional rates of PDF digestion (0.030 to 0.085/h), which implies that ruminative comminution may be first-limiting to fractional rate of PDF digestion. The in vivo roles of ingestive and ruminative mastication of fragments on PDF degradation must be considered in any kinetic system for estimating PDF digestion in the rumen. These results and others in the literature suggest that the rate of surface area exposure rather than intrinsic chemical attributes of PDF may be first-limiting to degradation rate of PDF in vivo. 相似文献