杉木幼龄林化学除草试验

1988～1989年,作者在开化、临安、龙泉3县试验点,采用8种除草剂,以不同剂量,混用或单用,对1～3年生杉木幼龄林作化学除草试验。结果表明:草甘膦+盖灌能除草除灌效果最好。化学除草与人工除草相比,每年可节约费用81.8～101.6元/hm~2.     

锦橙树冠光能分布对光合效应与结实的影响

锦橙树冠内各部位光能分布差异显著。光照对光合效应、结果和果实品质有明显的影响。在重庆地区11:00～11:30时,相对光照率南部>东部>西部>北部,15:00～5:30时则南部>西部>北部>东部。全天光强度均为叶幕外层>内层>树冠中心,叶幕上层>中层>下层。净光合速率、光合产物输出率及产量与光照有相似的变化趋势。各方位不同高度叶幕层的着果率与相对光照率呈极显著正相关。中层单果重分别比上、下层果高10%～26%和20.5%～52.9%。果实 Vc 含量,叶幕中层>上层>下层。固形物含量与光照率变化势相似。可食率、果酸变化与单果重相反。     

棉花种间杂种后代主要经济性状的对应分析

用对应分析法对８个棉花野生种的杂种后代共８３份材料的主要经济性状进行了分析。结果表明，对应分析不但揭示了材料间、性状间的相互关系，同时也揭示了性状与材料之间的相互关系；把８３份材料划分为１９个不同遗传差异的类群，可揭示出影响产量的主要因子是单株成铃和衣分，影响品质的主要因子是纤维强度和断裂长度。     

The land use patterns and the history of coffee in eastern Chiapas, Mexico

The role of coffee in the land usepatterns and decisions of eastern Chiapas looms as akey ingredient in the social and political relationsof this conflicted area. Data from the municipios of Ocosingo, Altamirano, and Las Margaritas – threedistricts generally associated with the January 1994uprising – reveal similarities and distinctdifferences in land use patterns involving coffee. Theintroduction and spread of coffee, as well as themarket and production changes related to this export-oriented sector can be linked to the colonists whosettled this remote region over the past severaldecades. The dynamics between grassrootscampesino producer organizations and the state'snow-defunct National Coffee Institute (INMECAFE)helped set the stage for the economic challenges thatfell full force upon the residents in the area in 1994and beyond.     

灰色关联度分析在油菜种质资源研究中的应用

首次将灰色关联度分析方法应用于油菜种质资源筛选和评价中,结果表明灰色关联度分析法可以明确资源筛选中的侧重点和资源对育种工作的价值大小,从而使油菜种质资源研究更加数量化并具有一定可靠性依据,避免以前工作中的盲目性。     

绿肥根茬培肥增产效应的研究

在草甸白浆土上对草木樨、秣食豆、黑麦草根茬的培肥增产效应进行了5年的研究,试验结果表明,强大的绿肥根系能够改善土壤理化性质,提高后作物产量。以5年粮豆总产量计,粮草轮作的产量较之粮豆轮作相等或略低。但在粮草轮作中,绿肥地多收鲜草(饲料)1350～1500kg/亩,总效益高于粮豆轮作。在绿肥全部翻压作肥料同只以绿肥根茬还田的对比中。后者的效益大于前者。     

Carbon in Amazon forests: unexpected seasonal fluxes and disturbance-induced losses

The net ecosystem exchange of carbon dioxide was measured by eddy covariance methods for 3 years in two old-growth forest sites near Santarém, Brazil. Carbon was lost in the wet season and gained in the dry season, which was opposite to the seasonal cycles of both tree growth and model predictions. The 3-year average carbon loss was 1.3 (confidence interval: 0.0 to 2.0) megagrams of carbon per hectare per year. Biometric observations confirmed the net loss but imply that it is a transient effect of recent disturbance superimposed on long-term balance. Given that episodic disturbances are characteristic of old-growth forests, it is likely that carbon sequestration is lower than has been inferred from recent eddy covariance studies at undisturbed sites.     

黑树莓的组织培养与快速繁殖

为了提供市场所需的大量苗木,适应树莓规模化生产的需要,以黑树莓的带芽茎段为外植体进行组织培养试验.经试验对比筛选出黑树莓的最佳分化培养基为MS+6-BA 0.2mg/L+NAA 0.2mg/L+Sugar 20g/L+Agar 6 g/L,生根培养基为1/2 MS+IBA 0.2mg/L+Sugar 20?g/L+Agar 6g/L,生根率达100%.在两步移栽法中,移栽存活率分别为98%和100%.     

蔗糖对黄金合果芋试管苗生长及生理的影响

试验研究了培养基中不同蔗糖浓度对黄金合果芋试管苗生长及可溶性糖含量、叶绿素含量的影响.研究结果表明：黄金合果芋试管苗叶片数、叶长、叶宽、株高和可溶性糖含量、叶绿素a、叶绿素b、叶绿素总量均随蔗糖浓度的升高而出现先上升再下降的动态变化.向培养基中添加蔗糖浓度以3%～4%为宜,有利于合果芋试管苗碳水化合物的积累,实现异养向自养的转化,促进生长,提高移栽成活率.     

“矮败小麦”株高的回交遗传效应

矮败小麦是太谷核不育基因 Ms2和矮秆基因 Rht10紧密连锁体,是一种具有矮秆标记性状的显性核不育新材料。其独特之处在于不育株接受任一非矮秆父本的花粉,后代总是分离出一半矮秆不育一半高秆可育。这在遗传育种中有极其重要的实用价值。为了利用好这个宝贵材料,我们用矮败小麦不育株为母本,40个普通小麦品种(系)为父本四年内连续回