温度条件对麦田土壤溶液养分浓度的影响

本文用实测资料分析了温度对麦田土壤溶液养分浓度的影响。研究表明,在农田土壤水分不亏缺的条件下,温度与麦田土壤溶液浓度呈正相关关系。随着太阳辐射增强,温度升高,土壤溶液中NO_3-N浓度增大,到14:00—15:00时,出现极大值。土壤溶液中钾浓度的高峰期基本是在中午温度高的时刻,低峰期在夜晚和午前10:00—11:00左右。10:00—11:00时的低值,可能与根系的同化吸收有关。土壤溶液养分浓度日较差大,光合面积增长快,营养生长旺盛。     

表油菜素内酯喷施时期对宽幅播种小麦产量和氮素利用率的影响

为明确协同提高宽幅播种小麦产量和氮素利用率的表油菜素内酯喷施时期,研究了不同生育时期喷施表油菜素内酯对小麦产量和氮素吸收利用的影响。结果表明: 与喷施清水对照相比,喷施表油菜素内酯可通过提高小麦穗粒数或(和)千粒重提高产量,通过促进地上部氮素积累提高氮素吸收效率,进而提高氮素利用率,但不同时期喷施效果存在差异。起身期+灌浆期、拔节期+灌浆期、起身期+拔节期+灌浆期、起身期+开花期+灌浆期喷施处理在所有处理中穗粒数和千粒重增幅最大,产量增幅最高(12.8%～14.0%);同时地上部氮素积累量增幅最大,氮素吸收效率增幅最高(16.4%～18.8%),从而氮素利用率增幅最高。综合施用成本等因素,生产上可采用起身期+灌浆期或拔节期+灌浆期2次间隔喷施模式,实现宽幅播种小麦高产高效栽培。     

Cytoskeletal arrangement and its intercellular connec-tion in wheat young leaf cells

By using the techniques of partial digestion of cell wall and selective extraction,we examined the cytoskeleton of wheat yong leaf cells under scanning electron microscope(SEM).A 3-dimensional cytoskeletal system,showing some new features,was observed.The cortical network located beneath the cross wall was an anastomosing organization.The association of nucleus with the cell wall by some skeletal filaments was also found.It is notice able that there were cytoskeletal filaments,which passed through cell wall and connected together with cytoskeletal arrays of adjacent cells,Thus,it is possible that an integral skeletal network existed within the yong leaf tissue of wheat.     

Effects of cadmium and lead on the accumulation of Ca2+ and K+ and on the influx and translocation of K+ in wheat of low and high K+ status

The effects of cadmium and lead on the internal concentrations of Ca²⁺ and K⁺, as well as on the uptake and translocation of K(⁸⁶Rb⁺) were studied in winter wheat (Triticum aestivum L. a. MV-8) grown hydroponically at 2 levels of K⁺ (100 uM and 10 mM). Cd²⁺ and Pb²⁺ were applied in the nutrient solution in the range of 0.3 to 1000 u.M. Growth was more severely inhibited by Cd²⁺ and in the high-K⁺ plants as compared to Pb^z+ and low-K⁺ plants. Ions of both heavy metals accumulated in the roots and shoots, but the K⁺ status influenced their levels. Ca²⁺ accumulation was increased by low concentrations of Cd²⁺ mainly in low-K⁺ shoots, whereas it was less influenced by Pb²⁺. The distribution of Cd²⁺ and Ca²⁺ in the plant and in the growth media indicated high selectivity for Cd²⁺ in the root uptake, while Ca²⁺ was preferred in the radial and/or xylem transport. Cd²⁺ strongly inhibited net K⁺ accumulation in high-K⁺ plants but caused stimulation at low K⁺ supply. In contrast, the metabolis-dependent influx of K⁺(⁸⁶Rb⁺) was inhibited in low-K⁺ plants, while the passive influx in high-K⁺ plants was stimulated. Translocation of K⁺ from the roots to the shoots was inhibited by Cd²⁺ but less influenced in Pb²⁺-treated plants. It is concluded that the effects of heavy metals depend upon the K⁺-status of the plants.     

In vivo binding of auxin to the plasmalemma and tonoplast of parenchymal cells in the wheat coleoptile

Tritiated auxin applied by an agar block on the wheat coleoptile tip for 2 hr was covalently fixed to adjacent protein by treatment with 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (DCC). The density of labelled auxin in the nucleus, the cell wall, the cytoplasm, and the vacuole was determined by autoradiography. Localization of tritiated auxin was studied at high resolution at the tonoplast and the plasmalemma lining the transverse (distal and proximal) and the longitudinal walls. The radioactivity along the tonoplast was always less than along the plasma membrane. The distribution of ³H-auxin was different across the longitudinal and transverse regions of the plasmalemma. The labelling was distributed asymmetrically on the longitudinal plasma membrane with a peak observed on the external surface. Tritiated auxin was distributed more symmetrically on the distal and the proximal plasma membranes. Our results are in agreement with the hypothesis that there are 2 different specific binding sites on the plasmalemma. The ratio of auxin present at the proximal and distal regions of the plasmalemma was 1.28.     

Use of agricultural surpluses for production of biomass by marine microalgae

The marine microalga Phaeodactylum tricornutum was cultivated in semi-continuous culture under mixotrophic conditions with the soluble fractions of potato, rye and wheat flours that had been naturally fermented, at 2% or 4% (w/v). The rye flour produced the highest microalgal cellular density of 90×10⁶ cells.ml^-1 when supplemented with NaNO₃ and NaH₂PO₄. The autotrophic control only gave 57×10⁶ cells.ml^-1. The value of agricultural surpluses, such as rye flour, can therefore be increased by its use in the production of valuable, microalgal biomass which is rich in protein, pigments and fatty acids.     

土壤水分和氮磷营养对冬小麦根系生长及水分利用的调节

模拟试验研究结果表明：在土壤相对含水量为４０％￣７０％范围内,水分亏缺严重,根水势和蒸腾蒸发量显著降低,根系生长严重受阻,根长变短,根干重降低,随着土壤水分趋于良好,根水势和蒸腾蒸发量显著增加,根干重在土壤相对含水量为５５％￣６２％之间时最大,而土壤相对含水量在５５％上下时根长达最长;土壤水分趋于轻度干旱有利根系下扎,土壤水分趋于良好利于根量增长。氮磷营养对小麦根系生长具有明显的调节作用。磷营养可     

环境中富啡酸对小麦吸收利用亚硒酸钠及其毒性的影响

利用小麦水培安验,研究了从土壤中提取的富啡酸（Ｆｕｌｖｉｃａｃｉｄ,ＦＡ）对亚硒酸钠生物有效性及毒性的影响。结果表明,富啡酸对小麦吸收利用亚硒酸钠有明显的影晌,并且对高浓度亚硒酸钠的毒性有一定的抑制作用,富啡酸可提高小麦对硒胁迫的生态适应性。     

冬小麦根表面氧化还原活力的研究

证实了两个不同品种的冬小麦根系表面存在着氧化ＮＡＤＨ和还原Ｋ３Ｆｅ（ＣＮ）６的氧化的活力。还原铁氰化物活力在ＰＨ５．５到８．５范围内随着ＰＨ值升高而增大,温度在１５℃到４５℃范围内随温度升高还原活力增强,４５℃达最高值,５５℃时活力急剧下降。     

小麦返白系与不同基因型小麦品种杂交后代IPO表达的研究

以小麦返白系和对照矮变１号以及返白系与各不同生态类型的冬性、半冬性、春性小麦的杂交、回交Ｆ１、Ｆ２代为材料,研究这些不同基因型品种在返白期间过氧化物酶同工酶（ＩＰＯ）基因表达模式的动态变化特点。结果表明,在返白期间以返白系为母本的各杂交、回交品种的白化苗中,ＩＰＯ的个别酶分子表现了可逆的基因阻遏和去阻遏的表达现象。这种表达特点在正、反杂交后Ｆ１代中表现一致,从遗传模式上分别属于质－核互作型的分子遗