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121.
笔者从石灰土在道路施工中的重要性出发,分析市政道路石灰土基层施工的前期准备工作,并介绍了市政道路石灰土基层施工工艺流程,最后分析了特殊季节道路石灰土基层施工的注意事项。 相似文献
122.
《Communications in Soil Science and Plant Analysis》2012,43(15-16):2536-2544
Recent soil‐management practices such as no‐tillage and minimal tillage, when applied to the irrigated rice crop, promote changes in soil composition as a result of anaerobic degradation of organic matter. Several short‐chain organic acids are formed, such as acetic acid. The objective of this work was to determine the effect of calcium (Ca) on plant development under stress by acetic acid toxicity. The experiment was conducted in hydroponics by testing different Ca (0.2, 1.0, and 5.0 mmol L?1) and acetic acid (0 and 2.5 mmol L?1) concentrations. The variables evaluated were the root system morphological parameters (total length, radius, area, dry‐matter weight, and main root growth), shoot parameters (shoot dry matter, plant height), and concentration and total accumulated nitrogen (N), phosphorus (P), potassium (K), Ca, and magnesium (Mg) in the plants. The growth of the root system and the shoots of rice plants were not affected by the addition of Ca to the treatments containing acetic acid. 相似文献
123.
124.
地膜覆盖下豆禾混播草地根系的动态研究 总被引:1,自引:0,他引:1
吴序卉 《甘肃农业大学学报》1999,34(2):120-124
使用差额法连续分层次地对燕麦+豌豆人工草地的根系在地膜覆盖条件下的生长发育动态进行了研究,结果表明:燕麦根系的58%分布浅,豌豆的77%根系分布在10~20cm深,两者混播后,其根系可有效地互补,且在地膜覆盖条件下互补性增强。同时地膜覆盖后,使根系的分布更浅,根量减少。 相似文献
125.
《Plant Production Science》2013,16(4):437-445
abstractNodal root anatomy was compared among twelve upland and lowland rice (Oryza sative L.) varieties with tropical origin which were grown in hydroponic culture and under field conditions. The traditional upland japonica varieties showed the largest diameter of root, stele, and xylem vessel followed by modern upland varieties. There was a clear varietal difference in the ratio of stele to root diameter, which was associated with the genetic group rather than with the ecosystems. The japonica varieties had a significantly larger stele diameter relative to the root diameter than indica and aus varieties. The indica and aus varieties displayed more xylem vessels per unit area of stele than the japonica varieties, but the diameter of xylem vessel was smaller. Equivalent xylem vessel diameter (De) was more dependent on the number of xylem in the indica varieties than in the japonica varieties. Distinctly different types of sclerenchyma anatomy were identified among the varieties. The development of sclerenchyma was classified into four different types based on thickening of cell wall in the outer cortical parenchyma and the number of sclerenchymatous cell layers. Like the xylem anatomy, the varietal differences in sclerenchyma development were more associated with genetic group rather than the ecotype. The japonica varieties had higher frequency of the types which have a doubled cell layer in sclerenchyma with thick cell wall than indica and aus. The difference among the genetic groups was nearly consistent across growing conditions, aerobic and submerged soils. These results indicated that sclerenchyma development is controlled by a genetic factor. 相似文献
126.
《Plant Production Science》2013,16(2):186-191
AbstractAnatomical observations were conducted to clarify some characteristics of the crown root primordia (CRP) formation in wheat stems. Unelongated portions of main stems were sampled from the plant at 3.2 and 7.2 plant age in leaf number, which were adopted as indexes because of the similarity to rice plants. Then, serial cross sections were made to investigate the position of CRP in the unelongated stem taking into consideration the running of vascular bundles in the stem. CRP were formed just outside tissues of the peripheral cylinder of longitudinal vascular bundles. The positions of CRP were not successive along the stem axis. They showed no definite relation to the running of vascular bundles. Diameters of CRP at the upper portion of the stems were larger than those at the lower portion. The positions of CRP along the stem axis were not distinguishable into nodal and internodal position. CRP and emerged CRs were not classified by the well-known ‘nodal root’ or ‘shoot unit root’, or the ‘unit’, which have been applied recently to rice plants. Further studies are necessary to clarify the factors controlling CRP formation anatomically and quantitatively. 相似文献
127.
128.
柔嫩艾美球虫(Eimeria tenella)体外细胞培养 总被引:3,自引:0,他引:3
试验比较了玻璃珠层析法,DEAE纤维素层析法,G3漏斗过滤法3种提纯柔嫩艾美球虫(Eimeriatenella)子孢子的方法,柱高8cm,直径200μm的玻璃株柱用pH8.0的Ringer’s缓冲液作洗脱提纯子孢子,回收率为64.1%,子孢子洗脱高峰期集中,且易于无菌操作,柱高5cm的DEAE纤维素柱用pH8.0的甘氨酸缓冲液作洗脱液,提纯子孢子回收率为63.2%,但严格无菌操作困难,G3漏斗法易 相似文献
129.
130.
无芒雀麦人工草地初级生产力动态的研究 总被引:3,自引:0,他引:3
以无芒雀麦人工草地为研究对象,对其生物量的季节及垂动态进行连续4a的研究。为促进无芒雀麦草地在河南省的高产丰收提供基础资料及其理论依据。 相似文献