中国野生假俭草的研究现状

对近年来我国野生假俭草的研究现状进行了综述,并提出了我国野生假俭草发展前景及今后科研的方向。     

假俭草和结缕草营养器官结构对抗逆性的影响

利用光学显微镜和电镜技术,采用石蜡切片法,叶片离析法等实验技术对假俭草和结缕草的茎,叶等营养器官的解剖结构特征和表皮微形态特征作了研究;通过角质层厚度,维管束数目,气孔指数,泡状细胞等数据分析它们之间的抗逆性差别;首次从微形态角度初步了解假俭草和结缕草及其不同种群之间抗旱力,耐践踏性差异的原因。     

假俭草(Eremochloa ophiuroides(Munro.)Hack.)种质资源改良研究进展

假俭草(Eremochloa ophiuroides(Munro.)Hack.)是主产于中国的世界著名的暖季型草坪草.全面系统地研究假俭草在遗传多样性和抗性生理等各方面的变异变化规律对于开发利用假俭草种质资源具有十分重要的意义.在综述假俭草种质资源的收集、整理和初步评价的基础上,重点介绍了近年来国内外在其遗传多样性(包括形态水平、细胞水平和分子水平)、抗性生理、育种进程和栽培管理措施等方面的研究进展.     

钾肥对假俭草草坪种群形成的影响

以四川峨眉山野生假俭草(Eremochloa ophiuroides L.)为实验材料,施以不同浓度的K肥(1.0～2.5g*m-2K2O),观察草坪种群形成过程.结果表明,1.0和 1.5 g*m-2K2O处理组假俭草的生长速度与对照差异显著(P< 0.05); 1.0, 1.5和 2.0 g*m-2 K2O处理组的平均分蘖数与对照的差异达极显著水平(P<0.01); 1.5 g*m-2K2O处理组根系长度与对照差异达显著水平(P<0.05);4 个处理组的根冠比分别比对照增加了 35.61%、50.61%、 21.91%和20.90%. 其中1.5 g*m-2 K2O处理组与对照差异达显著水平(P<0.05).低浓度处理(1.0和1.5 g*m-2 K2O)使草坪成坪时间提前3～5 d.钾对假俭草草坪种群形成有影响,适宜施用量为1.0～1.5 g*m-2 2O.钾肥主要在施用1～3周内起作用,5～10 d肥效高,而后逐渐减弱.     

中国假俭草结实性的比较分析

本文以中国有代表性的58份假俭草[Eremochloa ophiuroides(Munro)Hack．]种源为试验材料,以假俭草品种‘Common’和‘TifBlair’为对照,对中国假俭草的种子产量及其组分进行了统计分析。结果表明：中国假俭草种子产量平均为15．1g／m^2,花序密度平均为1510个／m^2,平均结实率为54．4％,平均百粒重0．086g,单位花序小花数平均为20．2。各组分变异系数从大到小依次为：花序密度、结实率、百粒重和单位花序小花数。假俭草种子产量高低主要由花序密度决定,结实率和百粒重也对种子产量有一定的作用,而单位花序小花数对种子产量贡献很小。不同种源种子产量存在显著性差异,产自重庆渝北的E092种源种子产量极显著高于品种‘Common’、“TifBlair’及其他种源;有14份种源的种子产量在24．8—39．5g／m^2范围内,均高于品种‘Common’,但均未达到显著水平;有17份种源的种子产量高于品种“TifBlair”,但也均未达到显著水平。     

Somatic embryogenesis and plant regeneration in centipedegrass (Eremochloa ophiuroides [Munro] Hack.)

Centipedegrass (Eremochloa ophiuroides [Munro] Hack.) is an important warm-season turfgrass and pasture grass. To explore the potential use of biotechnical tools in breeding of centipedegrass, we established an efficient plant regeneration system for this species. Four basal media and 24 combinations of 2,4-dichlorophenoxyacetic acid (2,4-D) and 6-benzyladenine (BAP) were examined for their effects on callus induction from mature seed explants. Twenty combinations of naphthaleneacetic acid (NAA) and BAP were tested for their effect on plant regeneration. Results indicated that Murashige and Skoog basal medium supplemented with 4.5 mg l⁻¹ 2,4-D and 1 mg l⁻¹ BAP was the best medium for callus induction, while the combination of 2 mg l⁻¹ BAP and 1 mg l⁻¹ NAA induced the highest rate of regeneration and development of shoots and roots. This work provides a basis for the breeding of centipedegrass through somaclonal variation and genetic transformation.     

Development of an embryogenic callus induction method for centipede grass (<Emphasis Type="Italic">Eremochloa ophiuroides</Emphasis> Munro) and subsequent plant regeneration

The present study demonstrates the establishment of embryogenic tissue from seeds and (seedling-derived hypocotyls) shoot base explants derived from seedlings of Eremochloa ophiuroides. The highest percentage of callus induction obtained from seed and young shoot base explants was 52.0% and 66.6% on Murashige and Skoog (MS) basal media supplemented with 9.0 μM and 18.1 μM 2,4-dichlorophenoxyacetic acid (2,4-D), respectively. The type of callus obtained from both types of explants was off-white to yellow in color and non-friable and shiny in texture. Excised callus from the explants was subcultured onto fresh media of the same recipe for further proliferation. After 10–12 d of subculture, a yellow, globular, friable embryogenic callus was obtained from the initial callus. The highest percentage of embryogenic calli obtained at 40.0% was observed on media containing 2.2 μM 2,4-D. The highest regeneration rate of 46.6% was observed on MS media supplemented with 0.4 μM 2,4-D and 2.2 μM benzylaminopurine (BA). Regenerated shoots were rooted in MS basal medium. Plants with well-developed roots were transferred to pots containing a soil mix and acclimatized in greenhouse conditions. Four weeks post-transfer, acclimatized plants showed 100% survival and remained healthy and green. This is the first report of a successful method for induction of somatic embryogenesis with subsequent plant regeneration in centipede grass and demonstrates the establishment of embryogenic callus and efficient plant regeneration with potential application in the development of genetic transformation systems for centipede grass.     

Morphological and Seed Set characteristics of Centipedegrass accessions collected in China

Greater than two-fold differences were observed between the lowest and highest means for stolon number and length characteristics. A 60% difference in total length was observed between the longest stolon of accessions. There was a 42% difference between the accessions with the fastest and slowest growing stolons. Accession with the longest and shortest internode differed by 28%. Small differences were observed for leaf length and width. Seed set under selfing was less than 7% indicating high self-incompatibility. Open-pollinated seed set ranged from 37% to 87%. Coefficients of variation for the various characteristics measured indicate that the Chinese accessions should provide more variation for genetic improvement in this species. Data showed that measuring total stolon length at five weeks after transplanting was adequate for evaluating all of the stolon length and number characteristics in this study. The Chinese accession appear to be a valuable source of new germplasm for this species.     

不同光照条件下假俭草生长格局的分形研究

应用分形几何的原理和方法,研究不同光照条件下假俭草的生长格局。结果表明,假俭草具有自相似性的生长过程。不同光照条件下,假俭草具有不同的分形维数和相应的生物量积累规律。生物量积累速率随着分形维数的增大而增大。分形维数同时反映了假俭草的分枝能力和对空间的占据能力。假俭草种群具有依据外界条件而调节生长格局的生态适应能力。