Changes in thyroid hormone levels in eggs and larvae and in iodide uptake by eggs of coho and chinook salmon,Oncorhynchus kisutsch andO. tschawytscha

Developmental profiles of thyroxin (T₄), triiodothyronine (T₃) and radioactive iodide uptake were established for eggs and T₄ and T₃ profiles were established for larvae (whole-body, yolk-only and body-only) of coho and chinook salmon. T₄ and T₃ were consistently present in all samples. In eggs, hormone levels remained fairly constant in all cohorst for at least the first three weeks of incubation, but then fluctuated in both directions in some sample groups. Large increases in T₄ (from 9 ng/g to 245 ng/g) were seen in 1985 chinook eggs 28 days after fertilization. Radioactive iodide uptake (which was used as a possible indicator of thyroxinogenesis) increased at least 10-fold in both 1986 coho and chinook eggs from 23–30 days after fertilization. T₄ (62 ng/g) and T₃ (393 ng/g) were found in the bodies of 28-day-old 1986 chinook embryos. In whole larvae, hormone levels varied depending upon the cohort studied. In general, initial body-only concentrations of both T₄ and T₃ decreased as body weight increased, but before yolksac resorption was completed, both thyroid hormone content and concentration increased (except for chinook T₃). T₄ and T₃ content in larval yolk stayed constant as yolksac size decreased, resulting in increased thyroid hormone concentration in the yolksac. All of these data suggest that the initial source of thyroid hormones in coho and chinook salmon eggs is maternal, but that by approximately 3–4 weeks after fertilization, the developing embryos begin to produce their own thyroid hormones. After hatching, increases in tissue T₄ and T₃ concentration coupled with constant T₄ and T₃ content in diminishing yolksacs suggest that larvae also produce their own thyroid hormones; yolksac content then may reflect both the original maternal hormones and the larva-producted hormones.     

Estradiol-17β-induced calcium uptake and resorption in juvenile rainbow trout,Oncorhynchus mykiss

Juvenile rainbow trout, Oncorhynchus mykiss, were injected with estradiol-17β (E₂) in order to study the source of extra calcium needed during vitellogenesis. E₂-treatment increased the calcium uptake from the external medium as well as calcium mobilization from muscle and scale. Judged by the increase in plasma protein-bound calcium levels, the E₂-induced increase in calcium uptake is an apparent over-mobilization of calcium, i.e., the calcium uptake of the fish is in excess of what is found bound to plasma proteins. As the calcium excretion and calcium space (calculated from free plasma calcium levels) were unaffected, the excess calcium is suggested to be incorporated into internal calcium stores. This implies that the systems regulating vitellogenesis and calcium balance are integrated on the mechanistic or endocrine level, and that E₂ causes calcium mobilization of a magnitude geared to the needs of the sexually maturing female.     

覆盖和粮草间作对作物氮素吸收利用和土壤硝态氮累积的影响

为了减少普通地膜和氮肥的投入,实现该地区农业生态良性循环和土壤的可持续利用,在甘肃武威试验站采用完全随机裂区设计,研究了不同种植模式（玉米单作、玉米//毛苕子和玉米//箭筈豌豆）和覆盖方式（普通地膜覆盖、生物可降解地膜覆盖、秸秆覆盖和无覆盖）对玉米和绿肥作物氮素吸收以及土壤硝态氮累积的影响。结果表明：覆盖和间作对作物的氮素吸收利用具有显著促进作用。玉米收获期,与无覆盖相比,普通地膜覆盖、生物可降解地膜覆盖和秸秆覆盖的玉米植株吸氮量分别增加21.46%,11.22%和34.63%,与玉米单作相比,玉米//毛苕子和玉米//箭筈豌豆的玉米吸氮量分别增加6.94%和6.26%。玉米收获期,秸秆覆盖的牧草植株吸氮量较普通地膜覆盖、生物可降解地膜覆盖和无覆盖分别增加46.75%,72.31%和21.76%,间作毛苕子的吸氮量较间作箭筈豌豆增加25.26%。玉米收获期,各处理玉米带、牧草（裸露）带0～140cm土壤硝态氮累积量均低于牧草收获期,无论牧草收获期还是玉米收获期,单作玉米的玉米带、裸露带土壤硝态氮累积量均低于间作玉米。玉米收获期,普通地膜覆盖和生物可降解地膜覆盖的玉米带0~140cm土壤硝态氮累积量较无覆盖分别显著增加32.87%和27.82%,普通地膜覆盖的牧草（裸露）带0～140cm土壤硝态氮累积量较生物可降解地膜覆盖、秸秆覆盖和无覆盖分别增加9.17%、6.07%和35.45%。     

Some proteolytic properties of hatching liquid in the sea trout,Salmo trutta m. trutta L.

Proteolytic activity of sea trout hatching liquid was examined towards casein and azocazein as a function of pH and temperature. The optimum pH for caseinolytic and azocaseinolytic activities were 9.4, and 9.0, respectively. At alkaline pH the enzyme was activated by low concentrations of Zn²⁺ ions (10⁻⁵ M). Maximum proteolytic activity of the hatching liquid was observed at 25°C. Temperatures exceeding 30°C caused a rapid reduction in enzyme activity. Proteolytic activity observed at 10°C was approximately 50% of that observed at 25°C. In general, a pseudo-Arrhenius plot indicated a Q₁₀ of 1.6 between 6 and 25°C.     

畜禽粪肥与化肥配施对春小麦产量和养分吸收利用的影响

为了解不同畜禽粪肥在春小麦生产上的应用效果,通过盆栽试验,在氮磷钾养分等量的情况下,比较分析了施用猪粪、牛粪、鸡粪和羊粪后春小麦产量和养分吸收利用的差异。结果表明,4种畜禽粪肥与化肥配施均能提高春小麦产量,促进养分吸收,提高肥料利用效率,培肥土壤,尤其以鸡粪与化肥配施效果最好。相比单施化肥处理,鸡粪与化肥配施处理的籽粒和秸秆产量分别提高13.43%和8.20%,籽粒和秸秆中的氮、磷和钾含量分别提高0.73%、9.74%、6.98%和2.86%、4.00%、9.19%,氮、磷和钾的累积量分别提高了14.27%、22.81%、22.81%和11.48%、11.11%、18.07%;氮素收获指数、氮肥农学效率、氮肥吸收利用效率、氮肥偏生产力和氮肥生理利用效率分别提高0.48%、52.77%、42.51%、13.46%和33.71%;磷素收获指数、磷肥农学效率、磷肥吸收利用效率、磷肥偏生产力和磷肥生理利用效率分别提高2.42%、52.77%、62.00%、13.47%和25.82%;钾素收获指数、钾肥农学效率、钾肥吸收利用效率、钾肥偏生产力和钾肥生理利用效率分别提高2.45%、52.77%、55.72%、13.47%和29.11%。土壤中有机质、全氮、全磷、全钾、碱解氮、速效磷和速效钾含量分别提高5.75%、10.94%、22.26%、1.95%、9.42%、26.85%和28.43%。     

钙信号抑制剂加剧低钾胁迫对烟草幼苗光合特性及钾吸收的影响

  【目的】  研究低钾胁迫抑制钙信号传导对植株幼苗叶片光合特性及钾吸收的影响,为缓解作物的低钾胁迫提供理论依据。  【方法】  以烟草品种K326为试验材料进行了室内水培试验。烟草幼苗先在营养液正常钾(K+ 5 mmol/L)和缺钾(K+ 0.15 mmol/L)营养液中生长8 天,然后在营养液中分别施加钙通道有机阻断剂Vp、钙通道无机阻断剂LaCl₃和钙离子螯合剂(EGTA)钙信号抑制剂,继续生长4天后取样,测定植株干鲜重、电导率、活性氧含量、叶片抗氧化酶活性、叶片光合特性等指标和植株地上、地下部钾素浓度及钾离子吸收相关基因表达量。  【结果】  1)不添加钙通道抑制剂或螯合剂条件下,低钾胁迫的烟株地上部和根系干重较常钾水平显著降低了59.29%、39.82%,鲜重显著降低了51.58%、48.19%,除水汽压饱和亏外的其余5项光合特性指标显著降低,植株地上部和根系钾含量分别显著降低了39.31%和77.05%,而叶中可溶性蛋白、相对电导率、过氧化氢含量则显著增加,NKT2、NtKC1、NtHAK1、NtHAK5基因的相对表达量分别增加了2.09、3.32、3.23、12.34 倍。2)常钾水平下,3个钙抑制剂处理未明显影响地上部和根系干鲜重,而低钾水平下,钙抑制处理的地上部鲜重和干重显著高于无钙抑制剂对照。两个钾水平下,与各自对照相比,3个钙抑制剂处理的叶片相对电导率、活性氧积累量均显著增加,抗氧化酶SOD和POD活性、叶绿素含量显著减少,光合特性指标(除水汽压饱和亏外)明显降低。3)两个钾水平下,3个钙信号抑制剂处理的烟株地上部和根系钾含量均显著低于其对照,低钾胁迫下平均降低幅度分别达到25.54%和53.36%。低钾胁迫下,钾离子通道基因NKT2、NtKC1和转运蛋白基因NtHAK1、NtHAK5在根系中的相对表达量分别平均降低了60.60%、50.62%、38.61%、69.79%,钙通道相关基因NtCNGC1和NtCNGC11在根中的相对表达量分别平均降低了95.36%和87.04%。  【结论】  低钾胁迫明显影响烟株幼苗生长、光合作用及对钾素的吸收和积累。低钾水平下,外施钙通道抑制剂或螯合剂可进一步降低烟草叶片抗氧化酶活性,减弱烟株叶片光合作用,并抑制根中钾吸收相关基因的表达和烟株对钾素的吸收。     

‘云蔗05-51’与‘云蔗081609’苗期氮吸收利用效率的比较研究

甘蔗（Saccharum spp. hybrid）是我国食糖生产的重要原料,当前生产中普遍存在施氮量高而氮肥利用率低的问题。除了优化施肥管理,种植氮高效的甘蔗品种也是减氮增效的重要途径之一。本研究以云南蔗区推广的早熟高产高糖甘蔗品种‘云蔗05-51’和‘云蔗081609’为试验材料,设置0、0.1、0.5、1、5、10 mmol/L 6个供氮水平开展水培试验,在苗期测定植株生物量、根系形态、氮浓度与累积量、氮素吸收利用效率等指标。结果表明：（1）2个品种地上部、根系及整株生物量均随供氮水平的升高呈先升后降趋势,‘云蔗081609’根系生物量先于其地上部达到峰值,‘云蔗05-51’则相反,‘云蔗05-51’和‘云蔗081609’达到最佳生长需要的供氮量分别为0.5、1 mmol/L,相同供氮水平下‘云蔗081609’生物量高于‘云蔗05-51’;（2）随供氮水平上升,2个品种的根系总长度和平均根直径先上升后趋于稳定,根表面积持续增加,比根长先升后降,相同供氮水平下‘云蔗081609’的根系总长度、平均根直径和根表面积高于‘云蔗05-51’,比根长则低于‘云蔗05-51’;（3）2个品种植株氮浓度及累积量随供氮水平的升高总体呈先上升后稳定的趋势,相同供氮水平下‘云蔗081609’的植株氮累积量高于‘云蔗05-51’;（4）随供氮水平的增加,2个品种的单位根长吸氮量呈先升后稳定的趋势,单位根表面积吸氮量则呈先升后降并趋于平稳,氮素生理利用效率均随供氮水平升高显著降低,在0.1~10 mmol/L范围内‘云蔗081609’单位根长的吸氮量高于‘云蔗05-51’,但单位根表面积吸氮量变化趋势基本一致,品种间氮素生理利用效率无差异。综上表明,‘云蔗081609’在苗期对氮的吸收量高于‘云蔗05-51’主要得益于更好的根系生长,苗期适宜需氮量低于‘云蔗05-51’。     

Utilization of Nano Rock Phosphate by Maize （Zea mays L.） Crop in a Vertisol of Central India

An attempt was made in the present investigation to utilize the vast deposit of rock phosphate （RP） of India by preparing nano RP using modem tool of nano-science and nano-technology for field application to maize crop （Zea mays L.）. To evaluate the efficacy of different nano RP, a field experiment was conducted during kharif season （June to September） of 2012 at India Institute of Soil Science （IISS）, Bhopal, taking maize as a test crop. The experiment consisted of five treatments （control, NK （100%）, NPK （100%）, NK （I00%） ＋ 60 kg P205） as nano RP through Udaipur nano RP （34% P205） and Udaipur nano RP （31% P205） were tested in randomized block design with four replications. The results showed that the shelling percentage, 1,000 grain weight, grain and stover yield, etc., were significantly higher in the maize plant treated with Udaipur nano RP （34% P205） as compared to the control, which was being at par with single super phosphate （SSP） treated plants. The total P content and its uptake were higher （0.65% and 40.29 kg/ha） in SSP treated plant, which was closely followed by Udaipur nano RP 34% （0.63% and 38.29 kg/ha） over the control （0.60% and 27.82 kg/ha）. The SSP treated plants had significantly highest apparent P recovery （47.98%） which was comparable to Udaipur nano RP （34% P205）, where as the Udaipur nano RP （31% P205） had the lowest. The additional N and K uptake by the plant was also observed with application of P sources, which were ranged from 16.5 kg/ha to 37.2 kg/ha and 27.9 kg/ha to 64.7 kg/ha under different P treatments. These results showed that crop utilization of P from nano RP was at par with that of P from SSP while yield response to P from nano RP was marginally lower than to P from SSP but serve as a cheaper source.     

有机、无机磷肥配施对宁夏引黄灌区露地蔬菜磷素吸收利用与磷平衡的影响

2011—2013年,在宁夏引黄灌区利用田间定位试验研究了不同有机、无机磷肥配施对露地蔬菜的产量、磷素吸收利用、土壤无机磷残留和磷平衡的影响,并提出了合理的磷肥投入阈值。结果表明,过量增施磷肥对露地蔬菜的增产作用不显著。露地蔬菜经济产量与施磷量都符合二次曲线关系,花椰菜、紫甘蓝和大白菜最大产量施磷量分别为P2O5332.3、304.5、377.8 kg/hm2,最佳经济施磷量分别为P2O5282.9、271.2、365.3 kg/hm2。增施磷肥能促进露地蔬菜地上部磷素吸收累积,磷肥利用率随化学磷肥用量增加而降低。随着施磷水平的提高,0~20 cm土壤Olsen-P和Ca Cl2-P含量都呈增加趋势。土壤磷平衡与施磷量呈线性正相关关系,化肥磷施用量越高土壤磷素盈余越大。2011—2013年花椰菜、紫甘蓝和大白菜季合理的磷肥投入阈值范围分别为[141.0,332.3]、[107.1,304.5]和[104.9,377.8],施磷量、蔬菜产量及地上部吸磷量是影响该阈值范围的主要因素。     

毛竹竹片化学染色的工艺参数研究

为了丰富竹片的颜色,提高竹产品的应用价值,采用染料染色的方法对竹片进行染色,探讨了前处理方式、染料种类、染色温度、染色时间、染液质量分数和助剂等对竹片染色效果的影响。结果表明,漂白、酸性大红、易渗剂10 mL等均较有利于竹片上染率的提高;染色温度对竹片上染率的影响极显著,随着温度的升高,上染率增加;随着染色时间的延长,竹片上染率呈逐步上升趋势;竹片上染率随着染液质量分数的增加呈现先升后降的趋势,质量分数约为0.7%时有最大上染率。较为优化的染色工艺:水浴温度控制在90℃左右,将经漂白的竹片置于质量分数为0.7%的酸性大红染液中水浴加热72 h,其间加入易渗剂10 mL。