株行距配置对玉米根系性状及产量的影响

以郑单958为材料, 采用田间试验方法, 在50 025株/hm²、67 500株/hm²、100 050株/hm²密度下分别设两种株行距配置, 探讨增密条件下调控株行距配置对玉米根系性状及产量影响。结果表明, 3个种植密度下总体表现为小行距种植方式在0～60 cm土层内的根重密度、根长密度及根表面积密度均高于大行距处理。50 025株/hm²下吐丝期时0～60 cm土层内的根重密度和根长密度在两个株行距配置间差异显著(P<0.05), 两个株行距配置的根表面积密度在10叶展、吐丝期和吐丝后25 d差异显著(P<0.05);67 500株/hm²下不同时期两个株行距配置根重密度差异显著(P<0.05), 根长密度和根表面积密度在10叶展和吐丝后25 d差异显著(P<0.05);100 050株/hm²下, 两个株行距配置间根重密度和根长密度在10叶展和吐丝后25 d差异显著(P<0.05), 不同时期根表面积密度差异显著(P< 0.05)。同一密度下缩行增株后单株木质部伤流液体积增大, 根系供应能力增强, 产量增加, 50 025株/hm²、67 500株/hm²下产量分别提高了6.76%和4.89%。不同时期0～60 cm土层内根重密度、根长密度和根表面积密度与产量呈正相关, 其中10叶展时各根系性状均与产量呈显著正相关。     

杨树组织特异性强启动子的筛选

为了筛选到具有木质部组织特异性并有较强功能的启动子，将河北林木种质资源与森林保护重点实验室前期已获得的MDCesA启动子、JCesAP启动子、DMDCesAP启动子（含2个串联MDCesAP启动子）融合GUS报告基因的pMDCesAP-GUS、pJCesAP-GUS、pDMDCesAP-GUS这3个植物表达载体，通过农杆菌介导转化杨树，对转化后的杨树进行GUS活性的定性及荧光定量检测，以比较3个启动子在转基因植物中的表达能力和水平。筛选到的组织特异启动子与抗天牛基因融合，将提高毒蛋白在相应部位的表达量，这对天牛类蛀干害虫的防治具有重大意义。     

增铵营养对番茄植株伤流液组分及含量的影响

在总氮(N)浓度相等的条件下,研究全硝营养(100% NO3-)和25% 增铵营养(NH4+∶NO3- = 25%∶75%)对开花期和幼果期番茄植株伤流液各组分含量的影响.结果表明,增铵营养显著增加幼果期伤流液中 K的含量,对Ca、Mg、P元素含量没有显著影响;增铵营养下伤流液中 NO3- 的含量下降、NH4+ 含量增加,氨基酸、苹果酸等的含量均显著增加,氨基酸/硝态氮含量之比显著提高,表明喜硝作物适当增铵不仅能够提高根系活力,显著促进K的吸收以供果实发育之需,而且提高了植株整体同化N素的能力.     

杨树木质部特异启动子MDCesAP的改造及功能检测

木质部特异表达的强启动子有助于外源目的基因在植物木质部中高效表达。将2个杨树木质部特异启动子MDCe-sAP串联在一起,置换植物表达载体pBI121上的35S启动子,构建成pDMDCesAP-GUS植物表达载体,通过农杆菌介导,并采用叶盘法转化烟草,获得烟草抗性植株。β-葡糖醛酸酶(GUS)活性检测结果表明,该串联启动子DMDCesAP具有木质部特异性,有望应用于桑天牛寄主树种的抗虫转基因研究。     

Leaf anatomical characteristics and physiological responses to short-term drought in Ziziphusmauritiana (Lamk.)

The aim of this work was to study the association between leaf anatomical characteristics and response to short-term drought stress in Ziziphusmauritiana Lamk. Six Z. mauritiana cultivars (Seb, Gola, Umran, Keitly, Q-29 and B-5/4) under field conditions in Israel's Negev desert were studied. Width of palisade mesophyll, spongy mesophyll and epidermis, xylem number and diameter in mid-vein were investigated with light microscopy. Short-term (3 weeks) drought stress tolerance was evaluated by monitoring plant response (leaf transpiration, diffusive resistance, chlorophyll fluorescence, leaf water potential and leaf relative water content). Greater epidermis and mesophyll widths and xylem diameters and densities were associated with increased tolerance to short-term water deficit expressed by preliminary wilting symptoms and proportional differences between initial and final physiological parameters. Significantly larger differences were found in Keitly, Umran and B-5/4 than in Seb, Gola and Q-29, indicating that the former cultivars are more sensitive to drought stress. Our results indicate that tolerance in descending order was Seb, Q-29, Gola, B-5/4, Keitly and finally Umran. The existence of an association between anatomical characteristics and short-term drought stress tolerance based on physiological responses is suggested.     

白桦木质部蛋白提取方法的建立1）

以白桦（ Betula platyphylla Suks．）木质部为试验材料,分别采用TCA—丙酮提取、酚提取和试剂盒提取3种方法提取白桦木质部总蛋白。利用试剂盒定量和聚丙烯酰胺凝胶电泳、双向电泳技术比较3种提取方法的蛋白质提取效率、提取质量。同时对酚提取法进行改良,建立适用于白桦木质部蛋白的提取方法。研究结果表明,改良的酚提取法提取的白桦木质部蛋白提取量最大,电泳条带清晰,丰富,质量较高。2－DE电泳得到的蛋白凝胶背景干净,蛋白质点清晰。因此,改良的酚提取法是较适合于白桦木质部蛋白的提取方法。     

Variation in Stemwood Nutrient Concentrations in Scots Pine Growing on Peatland

Radial and longitudinal variation in the nutrient concentrations of Scots pine (Pinus sylvestris L.) stemwood and the effect of fertilization (PK and NPK) were studied on three peatland sites in eastern Finland. The results showed distinctive patterns in longitudinal and radial nutrient concentrations in stemwood. The N, P and K concentrations were highest in the youngest tissues both in the radial and longitudinal directions independent of the site type or fertilization. Ca and Mn accumulated in the older parts of stemwood. Increased N, P, K and Ca concentrations were found 9 yrs after fertilization in the annual rings formed during the first-5-yr period after fertilization. Decreased Mn concentrations were found in the annual rings formed during the 5-and-9-yr periods after fertilization. The results indicate that in the intensive utilization of Scots pine stemwood, e.g. whole stem harvesting instead of stem harvesting to a fixed diameter (7-8 cm in Finland), nutrient loss increases proportionally more than the amount of harvested biomass. The results also imply that this wood contains more undesirable elements, such as K, which may cause problems in wood combustion in power plants, and that fertilization raises these concentrations in wood. However, the concentrations in unfertilized trees were generally at about the same level as in Scots pine stemwood grown on infertile mineral soil sites.     

The effect of bark decortication for hiwada production on xylem and phloem formation in Chamaecyparis obtusa

Of all plant materials used to cover the roofs of traditional Japanese buildings, Japanese cypress (Chamaecyparis obtusa) bark, hiwada, has the longest service life and has been used from ancient times. However, wood and bark properties after hiwada harvest have not been evaluated in detail. We studied whether decortication for hiwada production in winter affected xylem and phloem formation. Decorticated trees still preserved all inner bark and part of the outer bark, and both decorticated and control trees had similar annual ring structures at all stem heights in the xylem and phloem. In both xylem and inner bark, no significant difference in ring width at any stem height was found between annual rings before and after decortication. Thus, this study revealed that the decortication of bark for hiwada production does not affect the formation of xylem and the inner and outer bark if decortication is carried out by highly skilled workers in winter.     

Inhibiting factors of symptom development in several Japanese red pine (<Emphasis Type="Italic">Pinus densiflora</Emphasis>) families selected as resistant to pine wilt

Pinus densiflora and P. thunbergii, native to Japan, are highly susceptible to pine wilt disease caused by infection with a pine wood nematode (Bursaphelenchus xylophilus). Trees of these susceptible species have occasionally been found surviving in forests that are extensively damaged by this disease. Seedlings from a part of surviving trees that were selected as resistant families indicate lower mortality rates after the infection. The factors that prevent the symptoms from developing in resistant families of a susceptible species, P. densiflora, as based on the analysis of the pathogens behavior in the tree tissue and the anatomy of the resistant families, are presented in this paper. Nematode populations remained lower in the stems of seedlings from resistant families of P. densiflora than in the stems of non-resistant families. Areas dysfunctional in water transport developed in the stems of resistant families, but did not reach a size large enough to seriously block the ascent of sap. These results suggest that there are systems within the seedlings that prevent nematode migration and reproduction. The 2-year-old seedlings from resistant families of P. densiflora, however, did not suppress the pathogen activity. Numerous branches are a visible characteristic in the seedlings of some resistant families. The arrangement of the resin canals, the only channels in the tree to the pathogen migration, was disoriented at the joints between the branches and the main stem. Such a structure may be effective as a barrier to nematode dispersal.     

Photosynthetic response of white spruce families to drought stress

In the context of climate change, an increased frequency of drought stresses might occur at a regional scale in boreal forests. To assess photosynthetic responses to drought treatment, seedlings of 12 open-pollinated families of white spruce (Picea glauca (Moench) Voss) differing in their growth performance were grown in a controlled environment. Gas exchange and chlorophyll fluorescence parameters as well as shoot xylem water potential (WP) were measured for 21 successive days after watering was stopped. Net photosynthesis decreased as stomatal conductance decreased. Net photosynthesis was not affected by drought until WP reached –2.0 MPa when stomata were closed. Initial fluorescence (F and basic fluorescence after induction (F00) were not affected by drought. A progressive decrease in maximal (Fm) and variable fluorescences (Fv), maximum photosystem II (PS II) efficiency (Fv = Fm), effective quantum yield of PS II (FII), photochemical efficiency of open PS II (Fp), and photochemical quenching (qP) was observed at WP < - 1.0 MPa, whereas non-photochemical quenching (qN) remained high throughout the drought treatment. White spruce families with inferior growth performance showed higher values of Fm, Fv, Fv = Fm, Fp, and qN at WP< - 2.0MPa. The results indicated that chlorophyll fluorescence variables can be used as drought markers in relation to present or predicted climate conditions. These could be used for selecting planting stock adapted to drought periods or dry environments. These markers showed that slow-growing genotypes are better adapted to drought conditions than intermediate or fast-growing genotypes in present and predicted drought conditions.