湖南长沙地区13种观赏竹抗寒性研究

为研究已经在长沙地区进行引种栽培的地被观赏竹的耐寒性,以已选育的13种地被观赏竹为试验材料,通过在自然越冬状态下测定其叶绿素含量、丙二醛含量、相对电导率、超氧化物歧化酶活性、过氧化氢酶活性和脯氨酸含量,进行耐寒性研究。结果表明：在自然越冬下,13种观赏竹的叶绿素含量在不同月份和品种间的差异具有统计学意义(P＜0.01);除黄条金刚竹外,12种观赏竹的超氧化物歧化酶(SOD)活性和过氧化氢酶(CAT)活性升高,游离脯氨酸含量增加,丙二醛(MDA)含量和相对电导率增长较少;13种观赏竹的6项指标之间有显著相关性(P＜0.01);运用因子分析得13种观赏竹的抗寒能力排序为美丽箬竹(92.64)、湖南箬竹(89.08)、箬竹(86.66)、大明竹(86.56)、白纹椎谷笹(85.87)、白纹阴阳竹(85.04)、翠竹(85.03)、辣韭矢竹(83.88)、菲黄竹(82.73)、阔叶箬竹(82.53)、菲白竹(81.60)、鹅毛竹(80.18)、黄条金刚竹(62.67),与试验观察外表形态结果一致;黄条金刚竹受冻害明显,影响其观赏价值。     

矮秆基因对小麦不同农艺性状的影响

矮秆基因不仅降低株高，而且在许多情况下也影响其它农艺性状。利用小麦品种丰抗8号，北京841和京411遗传背景的近等基因系，研究矮秆基因对农艺性状的影响，结果表明：Rht10,Rht12延迟小麦抽穗期，Rht1b在丰抗8号背景下抽穗较迟，Rht1,Rht1s,Rht2和Rht3基因对轴抽穗期无影响；矮秆基因在降低株高的同时一般也降低单株生物产量，但含有Rht1,Rht1s,Rht1b,Rht2基因的矮秆系与对应的高秆系相比单株生物产量差异不显著，单株粒重差异也不显著，单株生物量的降低主要表现为秸秆重量的减少。含有Rht3,Rht10和Rht12基因的矮秆系与高秆系相比，单株生物量，单株籽粒产量和收获指数显著降低。     

山东苹果M26矮化砧木栽培适应性调查与评价

对山东省17个县(市)苹果M26矮化砧木的生产表现进行了系统调查,并对其栽培适应性做出了评价。结果表明:以M26为中间砧嫁接的富士,幼树生长势强,大树树体稳定性好,在山东省大部分地区表现出良好的抗寒性、抗旱性、抗风折性。     

2种矮化砧P22和SH3对富士苹果实生后代童期的影响

利用当年生富士苹果实生苗高位芽,嫁接到中间矮化砧木P22和SH3上,调查苹果实生苗度过童期的时间、始花部位和开花株数等,研究了2种矮化中间砧对富士实生苗童期的影响。结果表明：2种矮化砧均能明显缩短富士苹果实生苗的童期。用生长2 a的富士苹果实生苗嫁接在2种矮化砧木上,至少能够缩短童期2 a以上。但P22和SH3这2种矮化砧木缩短实生苗童期的效果存在较大差异,利用P22较利用SH3开花节数更少、开花高度更低、童期更短。利用2种矮化砧木的实生苗,开花平均高度均〉200 cm,平均节位数〉100节,且首次开花部位在侧枝顶花芽的占全部开花株数的50%以上。     

br-2玉米矮生系导入热带种质的应用研究

根据基因重组原理,利用隐性单基因br-2矮生基因导入热带种质,使抗病、窄叶片、优品质等性状与br-2矮生基因有机结合,有效克服矮生系节间短、叶片密集、授粉不良等缺点,成功选育配合力高的单基因br-2矮生系南381,由此组配的玉米单交种隆单9号在西南及南方大面积推广应用。     

矮壮素· 多效唑对鲜切花香石竹矮化的影响

[目的]筛选适宜鲜切花香石竹的矮壮素。[方法]以苔丝和激情为试验材料,分析不同浓度的矮壮素(CCC)、多效唑(PP333)对鲜切花香石竹苔丝和激情的生长的影响。[结果]不同浓度的矮壮素、多效唑都能使得鲜切花香石竹植株矮化,节间粗短,叶色深绿,研究结果表明矮壮素600倍液对鲜切花香石竹苔丝、激情矮化效果最佳。[结论]该研究可为鲜切花香石竹的生产提供参考。     

Relationships between the number of dwarf shoots of<Emphasis Type="Italic"> Larix decidua</Emphasis> Mill. damaged by different insect species in the Ojców National Park in southern Poland

A study was conducted on the interrelationships between the number of dwarf shoots of Larix decidua Mill. damaged by insects: Adelges laricis Vall. Coleophora laricella Hbn., Spilonota laricana Hein. and Dasineura kellneri (Hensch.). The study made use of dwarf shoots collected at three sites in the Ojców National Park, southern Poland during 2002–2003. A total of 240 branches with 19,239 dwarf shoots, collected from 60 larches were designated to the study. The data obtained were subjected to statistical analysis using the Spearman rank correlation coefficient and the Students t-test at the 0.05 level. No unequivocal correlation was found between the relationships.     

Tree regeneration in partially cut conifer–hardwood mixed forests in northern Japan: roles of establishment substrate and dwarf bamboo

We assessed the relationship of the regeneration (seedling and sapling) densities of seven representative tall-tree species to the past partial cutting and current stand structure. We also determined if differences in tree regeneration were associated to establishment substrates (coarse woody debris (CWD) and root throws) and understory inhibitor vegetation (the dwarf bamboo species: Sasa senanensis). The study was conducted in 17 conifer–hardwood mixed stands in a heavy snowfall region in Hokkaido, northern Japan. The results suggest that stand structure, rather than logging intensity, is the primary factor influencing regeneration densities. Total conifer basal area was positively correlated with the regeneration density of individual tree species, including two conifers and three hardwoods. These patterns differ from those observed in old-growth stands in the region. A negative correlation between total conifer basal area and dwarf bamboo coverage suggests that the presence of dense conifer canopies causes an increase in regeneration density of tall-tree species by preventing domination of dwarf bamboo. Picea glehnii, a species that depends for its establishment strongly on CWD, has lower seedling and sapling density in stands with higher logging intensity. This seems to be a result of the decrease in the volume of CWD with increasing logging intensity in these stands. We suggest that both reducing logging intensity and retaining overstory conifers should be considered to develop a sustainable silvicultural system in this region. Providing sufficient CWD and root throws may also be important to ensure natural regeneration of tree species that require these as an establishment substrate.     

Thinning and prescribed fire effects on dwarf mistletoe severity in an eastern Cascade Range dry forest,Washington

Forest thinning and prescribed fire practices are widely used, either separately or in combination, to address tree stocking, species composition, and wildland fire concerns in western US mixed conifer forests. We examined the effects of these fuel treatments alone and combined on dwarf mistletoe infection severity immediately after treatment and for the following 100 years. Thinning, burning, thin + burn, and control treatments were applied to 10 ha units; each treatment was replicated three times. Dwarf mistletoe was found in ponderosa pine and/or Douglas-fir in all units prior to treatment. Stand infection severity was low to moderate, and severely infected trees were the largest in the overstory. Thinning produced the greatest reductions in tree stocking and mistletoe severity. Burning reduced stocking somewhat less because spring burns were relatively cool with spotty fuel consumption and mortality. Burning effects on vegetation were enhanced when combined with thinning; thin + burn treatments also reduced mistletoe severity in all size classes. Stand growth simulations using the Forest Vegetation Simulator (FVS) showed a trend of reduced mistletoe spread and intensification over time for all active treatments. When thinned and unthinned treatments were compared, thinning reduced infected basal area and treatment effects were obvious, beginning in the second decade. The same was true with burned and unburned treatments. Treatment effects on infected tree density were similar to infected basal area; however, treatment effects diminished after 20 years, suggesting a re-treatment interval for dwarf mistletoe.     

小麦黄化型病毒病的研究

利用蚜虫传播、免疫电泳和超薄切片的电镜观察等方法对小麦田间新出现的四种黄化型病毒病进行了系统研究,确定是由大麦黄矮病毒所致,而不是小麦黄叶病。禾谷缢管蚜需要6小时可完成传毒,平均发病率为85%。大麦黄矮病毒粒子只存在和复制于植物韧皮部组织的筛管和伴胞内,病毒粒子大量聚集在细胞质内并在细胞质内形成“扭结”线状内含体。