百喜草研究进展

该文从百喜草的性状、营养器官、繁育技术、水土保持作用、林下开发技术、食用菌及饲料应用等 7个方面综述了百喜草的研究现状 ,指出了现有研究中存在的问题 ,并提出了百喜草未来的的研究重点。     

Impacts of ground cover on laws of temporal and spatial variation of soil moisture

In order to describe and compare intuitively the impact of different kinds of ground cover on temporal and spatial variation of soil moisture, an experiment was carried out by continuous observations to obtain soil potential data of different treatments. Based on the data, isogram maps were drawn by a regression isogram method. The results indicate that the isogram of treatment A (Paspalum notatum Flugge-covered) is the most complicated among the three treatments with its significant transverse levels, while the isograms of treatment B (mulching of P. notatum Flugge) and C (bare slope) are relatively simple but have clear vertical levels. The variation of soil moisture 30 cm deep in the A treatment is the largest, while that at 60 cm is the second largest and that of 90 cm is the smallest. The variation of soil moisture at all levels of B is fairly small, while that at 30 and 60 cm of C is greater than that 90 cm deep.     

Integration of pines and pastures for hay and grazing

When combining pine and cattle production on improved pastures, grazing may have to be delayed for several years until trees are large enough to resist injury. During this period forage would be lost unless harvested for hay. This study in south Georgia, USA, examined hay production during the first 3 years, cattle production during the next 3 years, and effects of this management system on survival and growth of slash pine(Pinus elliottii) planted in widely-spaced rows within the pastures. Pines were planted at 225 trees/ha in configurations of 3.0 x 14.6 or 4.9 x 9.1 m in pastures recently sprigged or seeded with Coastal bermudagrass (Cynodon dactylon) or Pensacola bahiagrass(Paspalum notatum). Pastures were fertilized annually and cut for hay four or five times each year. Wide-row spacings permitted haying operations, but tree rows and turning areas removed 5 to 8 percent of the area from production. However, hay yields and liveweight gains by yearling cattle were near normal for this locale. Slash pine planted in these fertilized pastures survived well, grew rapidly, and only a few trees were killed during haying operations. After 6 years, 83 percent of the trees survived and averaged 6.5 m in height and 13.2 cm in diameter. Cattle killed a few trees by rubbing during the 4th year. Wide-row spacing of pines permits harvesting forage for hay while waiting for the trees to become large enough to permit grazing. This approach to agroforestry produces annual returns to the landowner while awaiting maturity of the pines.     

60 Coγ射线辐照对海雀稗愈伤组织植株再生的影响

以海雀稗品种Adalay(Paspalum vaginatum Sw.cv.Adalay)的颗粒状胚性愈伤组织为材料,在离体培养条件下研究不同剂量的60Coγ射线辐照对愈伤组织绿苗分化和植株再生的影响。结果显示,辐照剂量在20～50Gy时,辐照处理的愈伤组织分化绿苗的频率从94%左右降至85%;剂量在60～80Gy时,愈伤组织的绿苗分化率从76%左右降至30%左右,相对植株再生率从44.5%降至8.7%。60Gy为辐照处理海雀稗颗粒状愈伤组织的适宜剂量,辐照处理的愈伤组织在附加BAP2.0mg/L的愈伤组织分化培养基上,绿苗分化率在76%左右,分化的绿苗转到附加NAA0.5mg/L的生根培养基上,相对植株再生率为44.5%。SRAP分子标记测定结果显示,特异性SRAP标记与体细胞辐照诱变突变体相关。本研究建立起海雀稗体细胞60Coγ射线辐照诱变技术,为在细胞水平上开展海雀稗辐照诱变育种提供条件。     

水土保持作物百喜草研究

 经长期筛选、观测及试验研究,其结果显示,百喜草为目前热带、亚热带最佳的覆盖作物。它具有耐瘠、耐旱、耐酸碱、耐踏、耐浸及中等耐荫等特性,种植于果园坡面、梯壁、沟渠、山边沟、边坡、农路等,不但可保护或延长设施的使用年限,达成了保育耕作及省工经营,而且绿化了坡地农场,也获得了环境保育的成效。40多年径流小区试验结果表明,百喜草对土壤冲蚀控制效果良好,降低泥砂的功效极为显着,亦能有限度降低洪峰流量,利于防洪。同时,百喜草是一种土壤优化作物和生态环境保育作物。     

大水位变化条件下护坡植物耐淹性研究

选用狗牙根、黑麦草、百喜草、葱兰和麦冬作为供试植物,在不同的淹水条件下,通过观测植物的表观特征和监测植物体内叶绿素含量、CAT和SOD酶活性等生理指标,结果表明,黑麦草与狗牙根在全淹10d后相继死亡;百喜草、葱兰和麦冬在全淹状态下CAT的相对含量呈上升趋势,且百喜草、葱兰和麦冬在全淹50d后仍能够成活。百喜草、葱兰和麦冬能够适应在大水位变化条件下护坡上生长。     

不同胁迫条件下决明对百喜草的化感作用

探讨在温度、pH值和模拟干旱（聚乙二醇）胁迫条件下,圆叶决明和羽叶决明对百喜草的化感作用。结果表明,在不同温度处理条件下圆叶决明和羽叶决明对百喜草种子发芽、苗高和根长的影响总体上表现是温度高（27℃）时和温度低（23℃）时均对百喜草种子发芽有抑制作用,而温度在25℃则表现出促进作用;在3个不同浓度聚乙二醇（PEG）胁迫下,决明对百喜草生长均表现出一定的抑制作用,其中在PEG浓度为20%时抑制最为明显;不同酸碱度（pH）胁迫下决明对百喜草的影响总体表现是高pH抑制,低pH促进。     

不同施磷浓度对柱花草和黑籽雀稗根系分布的影响

采用根箱法,结合Winrhizo2004a根系扫描测定系统,以豆科牧草柱花草和禾本科牧草黑籽雀稗为试验材料,研究不同施磷水平对柱花草和黑籽雀稗根系分布的影响。结果表明,2种牧草根系分布随土壤深度的增加而减少, 柱花草集中分布于0～10 cm土层, 黑籽雀稗集中分布于0～20 cm土层;磷对2种牧草根系生长的影响存在较大的差异。低磷(P1,0.48 g P₂O₅/kg土)更适合柱花草根系和地上部分的生长,高磷(P3,1.92 g P₂O₅/kg土)水平对根系生长有抑制。黑籽雀稗对磷的需求量大,随着磷施入量的增加,根干重、总根长、根表面积、体积和根系平均直径均有所提高。     

2种雀稗属牧草种子休眠机理及其破除方法研究

以2种雀稗属牧草种子为材料,从种子的吸水性、浸提液活性的生物测定和GA3、ETH、IAA等外源激素浸泡处理等角度,研究2种雀稗属牧草种子休眠机理及破除方法.结果表明:1)2种雀稗属牧草种子生活力均达到92.2％以上,但发芽率较低.宽叶雀稗和巴哈雀稗的发芽率分别仅为59.3％和10.0％,都具有明显的休眠现象.2)2种雀稗属牧草种子的种皮均不限制种子吸水,但巴哈雀稗种子种皮对种子萌发有机械障碍.3)2种雀稗属牧草种子浸提液对白菜种子及自身萌发具有明显的抑制作用,说明2种雀稗属牧草种子内源抑制物含量较高.可知,宽叶雀稗种子休眠属于生理休眠,巴哈雀稗种子休眠属于综合休眠.4)GA3、IAA、ETH、H2SO4及复合处理对宽叶雀稗种子萌发均有不同程度的抑制作用.GA3、H2SO4及复合处理对巴哈雀稗种子萌发有促进作用.H2SO4处理5 min巴哈雀稗种子效果最佳,可提高发芽率35.3％.     

热研11号黑籽雀稗染色体核型分析

试验采用了染色体压片法研究了热研11号黑籽雀稗Paspalum atratum cv.‘Reyan11’的染色体数目和核型。结果表明:热研11号黑籽雀稗的染色体数目2n=40,核型公式为2n=2x=40=32m+4sm+2st+2M。核型分类为"2A"型,比较对称。研究确定了热研11号黑籽雀稗染色体的数目,并分析了其核型,这为热研11号黑籽雀稗的起源演化及分子生物学提供了细胞学研究基础。