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牦牛放牧率对小嵩草高寒草甸不同植物类群地上生物量生产率的影响 总被引:1,自引:0,他引:1
2年的牦牛放牧试验表明:除不同植物本身的生理特性外,降水和地温是影响小嵩草高寒草甸两季草场不同植物类群地上生物量绝对生长率的关键因素。小嵩草高寒草甸两季草场地上总生物量的绝对生长率1999年在7月份最大;1998年,冷季草场各放牧处理的绝对生长率在8月份达到最大,暖季草场的对照组和轻牧组在7月份最大,中牧组和重牧组在8月份最大。不同植物类群地上生物量生长率的变化不尽相同。1998年,冷季草场禾草和莎草地上生物量的绝对生长率8月份达到最大,暖季草场禾草和莎草地上生物量的绝对生长率7月份达到最大,且9月份出现了营养的再次积累;1999年,冷季草场禾草地上生物量的绝对生长率在6月份和8月份出现了两个峰值,暖季草场禾草地生物量的绝对生长率在7月份达到最大。对杂草类而言,1998年冷季草场的绝对生长率6月份最大,暖季草场重牧组的绝对生长率8月份达到最大,其他各处理7月份达到最大;1999年重牧组杂草的绝对生长率在6月份达到最大,其他各处理杂草在8月份达到最大。 相似文献
13.
The effect of separate chilling (5°C for 2 and 4 days) on the shoots and roots of two maize hybrid seedlings on the electric potential, the composition of fatty acids and the ATPase activity in the microsomes of non-chilled leaves and roots (20°C) was investigated. It has been found that the low temperatures induced on the non-chilled organs gave similar changes to organs exposed to a reduced temperature. The changes consisted of a parallel depolarization of leaf and root membranes and similarly a decrease in the ATPase activity as well as changes in the unsaturation of the membranes' fatty acids. The reduction of the acid content 18:2 was particularly significant, which in the leaf microsomes correlated with a drop in the ATPase activity.
The similarity between the reactions of the chilled and non-chilled parts of the plant gives evidence of a communication' between the organs which may facilitate a coordinated reaction of the entire organism to stress. The background for these phenomena could be die action potential of die chilled parts of seedlings which, in the non-chilled parts, might produce changes in the structure of biomembranes and in the activity of enzymes. 相似文献
The similarity between the reactions of the chilled and non-chilled parts of the plant gives evidence of a communication' between the organs which may facilitate a coordinated reaction of the entire organism to stress. The background for these phenomena could be die action potential of die chilled parts of seedlings which, in the non-chilled parts, might produce changes in the structure of biomembranes and in the activity of enzymes. 相似文献
14.
WANG Xiaoxiao MA Qiangqiang CAO Xiaojun . Wuhu Luhuan Company Ltd. of Landscape Architecture Wuhu P.R.China . Northwest Minorities University Lanzhou P.R.China . The Scientific Technological Incorporated Company of Donghua Engineering Hefei P.R.China 《中国林业科技(英文版)》2005,4(2):36-43
1 GENERALRoof gardens can be extensively interpreted as ageneral designation, which means building variousrecreational garden on roofs, gazebos and terracesof both ancient and modern buildings, structures, andbridges (flyovers) (Jin Weiping, 1996). Cities aredensely populated and land is costly, so shortage ofland is one of the restrictive factors in green urbandevelopment. According to statistics, the green spaceis 2~3 m2 per capita in Chinese cities. As a result, todevelop roof gardens h… 相似文献
15.
ABSTRACT: The reproductive traits and the monthly larval abundance of the mantis shrimp Oratosquilla oratoria were investigated in Tokyo Bay, Japan, in 2002. The goal of the study was to elucidate the cause of changes in the monthly pattern of larval abundance from the 1980s to the 1990s as these changes relate to variation in the stock size of the adult shrimp. Oogenesis was divided into 10 stages by histological observation. The developmental stage of oocytes in an individual's ovary was synchronous, suggesting that almost all the oocytes in an ovary are spawned at the same time. The size at first maturity was estimated to be 7 ≤ body length ( BL ) < 8 cm. Fecundity was expressed as a function of BL , ranging from 19 300 eggs for 8 cm BL to 92 100 eggs for 14 cm BL . Small female shrimps (<10 cm BL ) spawned around August. Most large female shrimps (≥10 cm BL ) spawned around May, and some large female shrimps also spawned until September. Although most large female shrimps spawned in spring, the larval abundance was low before July and high from August onwards. The results suggest that a substantial decrease in the stock size of large individuals causes the low larval abundance before July. 相似文献
16.
Totally 13575 ewes of two different breeds, Dala and Spel, were inseminated with semen, frozen in straws and thawed at 70°C for 8 sec. An insemination dose of 0.2 ml containing approx. 150 × 106 spermatozoa with at least 45 to 50% progressive motility was imerted 5 to 12 mm into the cervix. The insemination was performed once between 12 and 30 h after the onset of heat. The NR rate of the Dala ewes increased significantly during the season. The NR rate of the ewes inseminated before 15. November was 44.3%, from 15. to 20. November 52.2%. from 20. to 25. November 55.3% and from 25. November and later 61.4%. The corresponding values for the ewes of the Spel breed were 57.3, 58.7, 61.5 and 71.0% respectively, and only the difference between the two last values was statistically significant. The difference between the fertility of the two breeds was significant within each of the periods . 相似文献
17.
在牧草生长季节(5~9月)对小哨牧场放牧演替形成的5个草地型草地的牧草进行生长速率、牧草产量及养分的逐月观测,生长速率测定显示,白三叶+东非狼尾草和东非狼尾草+非洲狗尾草两个草地型草地均出现两个生长峰值,分别在6月和9月,其余3个草地型草地只有一个生长高峰。干物质产量和牧草养分测定结果表明,白三叶+东非狼尾草和白三叶+非洲狗尾草+画眉草两种草地型草地表现最好,可以在气候环境条件类似的地区推广种植利用;白三叶+画眉草和白三叶+非洲狗尾草两种草地型草地表现优良,可以在草地改良中,根据当地实际情况选择性地加以种植;东非狼尾草+非洲狗尾草型草地表现较差,不提倡种植。 相似文献
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19.
本试验选用3头6月龄左右断奶中国荷斯坦公牛,在试验全程喂以相对稳定的日粮,从2003年11月1日开始,到2004年6月20日结束,用以测定中国荷斯坦生长公牛在不同生长期对饲粮中各营养成分的代谢情况。试验结果表明:日粮中的DM、OM、NDF、ADF、淀粉和粗蛋白质的表观消化率随着生长犊牛的月龄的增加而增加(P<0.05);并且9月龄以后,DM、OM、NDF、ADF和粗蛋白质的表观消化率增长不明显(P>0.05),淀粉的表观消化率则在11月龄以后增长不明显(P>0.05)。氮的净吸收率随着生长犊牛的月龄的增加而下降(P<0.05),且在9月龄以后下降不明显(P>0.05)。 相似文献
20.
番鸭在南京地区进行冬、夏两批饲养,均有较强的适应性。试验结果表明:冬、夏两 批饲养的番鸭只平均重量差异不显著(P>0.05)。夏季与冬季的料重比分别为1:2.62和1: 3.07,冬季饲养的鸭子饲料利用率低,料重比大于夏季。冬季在塑料大棚中饲养番鸭精饲料减 少1/3,添加青粗饲料能达到同样的增重效果。温度与增重无相关关系,相对湿度与番鸭的增 重呈负相关(P<0.01)。鸭舍内平均温度在11.05℃-30.93℃之间,相对湿度在76.28%以 下,番鸭能正常生长发育。环境温度在9.8℃以下,番鸭的生长发育受阻,饲料利用率降低。相 对湿度在77%以上,其增重受到影响。特别在低温高湿的环境中,严重地影响番鸭的生长。在 相同的饲养期内,周平均温度9.8℃,平均相对湿度91%,番鸭周平均增重22 g,周平均温度 27.42℃,平均相对湿度71.29%,番鸭周平均增重355 g,相差333 g(P<0.01)。 相似文献