陕西关中小麦品种更替中性状演变及其发展方向

以关中地区四十年代到九十年代推广种植的主要代表品种及品系为材料,对其分蘖动态、生育期、株高因素、穗部性状、产量、生物学产量、经济系数及冬春性等２０个性状进行了研究,其结果表明关中地区四十代到九十年代小麦品种性状演变的趋势是：冬、春季分蘖变化不大,冬季分蘖趋向略增;春季分蘖趋向略减;成穗数趋向降低,拨节,抽穗和开花期有趋早倾向,而成熟期和总生育天数无明显变化,株高降低极明显（１３７．７－８５．２ｃｍ     

合理用药生态控制茶小绿叶蝉主要措施与评价

合理用药生态控制茶小绿叶蝉主要措施与评价张觉晚,王沅江（湖南省茶叶研究所,长沙４１０１４５）ＰｒｉｎｃｉｐａｌＴｅｃｈｎｉｑｕｅｓｏｆＲａｔｉｏｎａｌＵｓｅｏｆＰｅｓｔｉｃｉｄｅｆｏｒＥｃｏｌｏｇｉｃａｌＣｏｎｔｒｏｌｏｖｅｒＴｅａＧｒｅｓｎＬｅａｆ...     

铅锌矿尾矿场植被重建的生态学研究Ⅰ.尾矿对种子萌发的影响

在实验条件下,供试的林木、农作物及牧草种子均能在铅锌矿尾矿中萌发,其中萌发率与非污染土壤中的相近,多数种子的萌发速率低于对照组。供试植物幼苗出土30天内没有死苗现象,但与对照相比,株高下降28.4%,复叶数减少34.1%,生物量下降52.6%.     

“8455”小麦植株化学成分与麦蚜（长管蚜、二叉蚜）种群消长的关系

通过对两种肥力条件下的“8455”小麦植株化学成分与麦长管蚜和麦二叉蚜种群消长关系的研究与分析,结果表明可溶性糖、含钾量、含水量是影响麦二叉蚜种群消长的主要因子,胱氨酸是影响麦长管蚜种群消长的主要因子。     

麦秸覆盖夏玉米对其苗期生长发育的生化他感作用研究初报

麦秸覆盖夏玉米对其苗期生长发育的生化他感作用研究初报张玉铭,马永清（中国科学院石家在农业现代化研究所,０５００２１）ＡｌｌｅｌｏｐａｔｈｉｃＥｆｆｅｃｔｏｆＷｈｅａｔＳｔｒａｗＭｕｌｃｈｉｎｇｏｎＳｅｅｄｌｉｎｇＧｒｏｗｔｈａｎｄＤｅｖｅｌｏｐｍｅｎ...     

pCMBS对完整红细胞膜阴离子通透性的影响

根据等渗ＮＨ４Ｃｌ溶血动力学,探讨了ｐＣＭＢＳ（对氯汞苯磺酸）对完整红细胞膜阴离子通透性的影响．０．０５ｍｍｏｌ／ＬｐＣＭＢＳ使阴离子通透系数Ｐｃｌ下降为对照的８６．５％;１．０ｍｍｏｌ／Ｌ以上浓度时Ｐｃｌ值反而变大。ｐＣＭＢＳ浓度高于０．３ｍｍｏｌ／Ｌ时,细胞悬浮液在１０ｓ之前光密度下降过快,偏离理论拟合方程且不受ＤＩＤＳ抑制．半胱氨酸对ｐＣＭＢＳ引起的效应有恢复作用。结果表明ｐＣＭＢＳ和股骨架蛋白上特殊－ＳＨ基相互作用,导致ｂａｎｄ３构象改变,致使改变膜时阴离子的通透性。     

细胞电穿孔动态过程的荧光测量

利用改进后的Ｔｈ／ＤＰＡ荧光方法及探针ＥＢ对人血影及大鼠骨髓细胞电穿孔的动态过程及其与电脉冲参数的关系进行了系统的研究．测量结果表明,在临界点以上电场作用下,血影电穿孔在电击后０．２—０．３ｓ时达最大,在约０．８ｓ时愈合;而大鼠骨髓细胞电穿孔在电击后０．４—０．９ｓ达到最大,３－５ｓ左右愈合;电穿孔大小及扩大、愈合速率与电脉冲参数有关。１０－４０ｍｍｏｌ／Ｌ乙醇和５－２０ｍｍｏｌ／Ｌ成二醛抑制血影对Ｔｂ３＋离子的电通透,相同浓度的成二醛作用强于乙醇。这些结果将为电穿孔技术的合理应用提供参考。     

锌离子对氨基酰化酶构象及其稳定性的影响

天然氨基酰化酶和脱谷氨基酰化酶无论在二级结构（用ＣＤ和ＦＴＩＲ监测）还是三级结构上（以荧光发射光谱监测）都有明显的差异,表明了脱锌后酶的有序度降低;当比较天然和脱锌氨基酸化酶对去圬剂的稳定性时,结果表明脱锌后酶的构象的稳定性明显降低．因此可以认为锌离子对维持酶分子活性部位的特定构象以及构象的稳定性具有重要的作用．     

Genetic differentiation in carbon isotope discrimination and gas exchange in Pseudotsuga menziesii

Patterns of genetic variation in gas-exchange physiology were analyzed in a 15-year-old Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) plantation that contains 25 populations grown from seed collected from across the natural distribution of the species. Seed was collected from 33°30 to 53°12 north latitude and from 170 m to 2930 m above sea level, and from the coastal and interior (Rocky Mountain) varieties of the species. Carbon isotope discrimination () ranged from 19.70() to 22.43() and was closely related to geographic location of the seed source. The coastal variety (20.50 (SE=0.21)) was not significantly different from the interior variety (20.91 (0.15)). Instead, most variation was found within the interior variety; populations from the southern Rockies had the highest discrimination (21.53 (0.20)) (lowest water-use efficiency). Carbon isotope discrimination (), stomatal conductance to water vapor (g), the ratio of intercellular to ambient CO₂ concentration (c_i/c_a), and intrinsic water-use efficiency (A/g) were all correlated with altitude of origin (r=0.76, 0.73, 0.74, and –0.63 respectively); all were statistically significant at the 0.01 level. The same variables were correlated with both height and diameter at age 15 (all at P0.0005). Observed patterns in the common garden did not conform to our expectation of higher WUE, measured by both A/g and , in trees from the drier habitats of the interior, nor did they agree with published in situ observations of decreasing g and with altitude. The genetic effect opposes the altitudinal one, leading to some degree of homeostasis in physiological characteri tics in situ.     

Different Localization of Two Ca2+ in Spinach Oxygen-Evolving Photosystem II Membranes. Evidence for Involvement of Only One Ca2+ in Oxygen Evolution

Localization of the two Ca²⁺ bound to oxygen-evolving photosystemII (PSII) membranes from spinach was investigated by fractionatingthe membranes into the PSII reaction center core complexes andperipheral antenna Chl a/b-proteins after solubilization withn-heptylthioglucoside. The core complex fraction contained oneCa²⁺ per PSII, while another Ca²⁺ was found in the solubilizedmajor light-harvesting Chl a/b-proteins (LHCII). LHCII isolatedwith Triton X-100 or dodecylmaltoside also contained Ca²⁺ inan amount corresponding to one per PSII. The Ca²⁺ bound to LHCIIcould not be removed by treatment with Chelex 100, which effectivelysequestered extraneous Ca²⁺ bound to LHCII, or by preparationof LHCII in the presence of 40 mM citrate. Localization of thetwo Ca²⁺ in different functional domain of PSII membranes conclusivelyindicates that the number of the bound Ca²⁺ that can functionin oxygen evolution is one per PSII. The results also suggestthat one Ca²⁺ has a structural role in the peripheral antennaassembly. (Received July 21, 1992; Accepted March 9, 1993)