冷害胁迫下3个狗牙根品种抗寒性比较研究

对冷害胁迫下3个狗牙根Cynodon dactylon品种的抗寒能力和超氧化物歧化酶(SOD)、过氧化物酶(POD)及POD同工酶的变化进行研究,结果表明:根据低温下细胞膜的伤害程度,3个狗牙根品种抗寒能力的强弱顺序为新农一号狗牙根C.dactylon cv.Xinnong No.1>喀什狗牙根C.dactylon cv.Kashi>矮生天堂草C.dactylon×C.trasvaalensis,且在根茎上反映更加明显;POD,SOD的活性均表现出先上升后下降的趋势,植株抗寒能力的强弱可能与它们的活性及其持续时间的长短有一定的正相关性;聚丙烯酰胺凝胶电泳表明,抗寒性越强的狗牙根品种POD同工酶条数也越多,且在冷害适应中未有新的同工酶谱带出现.     

Na2SO4胁迫下狗牙根K+、Na+离子分布及其抗盐性的评价

通过对盆栽狗牙根(新农一号狗牙根)、喀什狗牙根、C-3(狗牙根品系)、矮生天堂草以0、0.4%、0.8%、1.2%、1.6%五个土壤盐浓度进行处理,对其K+、Na+离子变化情况做了研究.结果表明相同盐浓度水平下,狗牙根体内K+、Na+离子含量茎叶大于根系,茎叶是K+、Na+离子累积的主要部位;K+/Na+比茎叶大于根系,说明茎叶耐钠性大于根系;随着盐度水平的递增,新农一号狗牙根、喀什狗牙根、C-3狗牙根K+、Na+离子吸收选择性系数增大,新农一号狗牙根＞喀什狗牙根＞C-3＞矮生天堂草.由此初步认为,狗牙根抗盐性从大到小依次为新农一号狗牙根＞喀什狗牙根＞C-3狗牙根＞矮生天堂草.     

新疆狗牙根农艺性状及利用价值初探

对新疆具有代表性的7份狗牙根Cynodon dactylon材料的12项农艺性状进行初步研究表明,新疆狗牙根种内差异大,具有培育优良新型牧草或草坪品种的潜力,其中C5植株高大、茎秆粗壮、叶片大、草产量高,C1植株矮小、茎秆及叶片纤细、颜色深绿,其余材料居中;通过农艺性状聚类分析,结合加权综合评价结果,初步将新疆狗牙根划分为3个类型,即草坪草牧草兼用型(包括喀什狗牙根、新农一号狗牙根、C4、C3)、草坪型(C1、C2)、牧草型(C5),为今后新疆狗牙根种质资源的进一步开发利用提供科学的依据。     

狗牙根对不同干旱胁迫处理的生理响应

以无土基质培育的狗牙根(Cynodon dactylon)为研究对象,研究了狗牙根对不同干旱胁迫处理的生理响应,以探讨工厂化培育下狗牙根合理的灌溉时间.结果表明,干旱胁迫导致叶片相对含水量降低,游离脯氨酸含量和超氧化物歧化酶活性增加,在干旱胁迫12 d以前复水的处理,叶片相对含水量和游离脯氨酸含量能恢复到未处理以前,在...     

冬季覆盖物对山西野生狗牙根形态特征和生理特性的影响

利用塑料薄膜覆盖、遮阳网覆盖和草帘覆盖,观测野生狗牙根(Cynodon dactylon)返青初期叶片、茎和根茎各组织器官的形态特征,测定叶绿素含量、相对含水量、可溶性糖、可溶性蛋白含量和保护酶活性等生理生化指标,以揭示不同覆盖处理下狗牙根各组织器官的生理响应.结果表明:经覆盖处理的狗牙根返青率在88.67%以上,而未覆盖的狗牙根植株全部死亡;草帘覆盖处理的狗牙根草坪盖度、株高、叶绿素含量显著高于遮阳网覆盖,而丙二醛含量及质膜透性显著低于遮阳网覆盖,效果最好;塑料薄膜次之,遮阳网较差.狗牙根各器官对覆盖物的响应表现出根茎 >叶片 >茎.     

云南高尔夫球场草坪杂草调查及防除对策

对春城高尔夫球场草坪常见杂草进行调查.结果表明:春城高尔夫球场草坪常见杂草共19种.通过分析,球场草坪杂草优势度依次为一年生早熟禾Poa annua(63.14%)＞白茅Imperata cylindrical(14.68%)＞狗牙根Cynodon dactylon(11.45%)＞白三叶Trifolium repens(5.56%)＞水蜈蚣Kyllinga brevifolia(2.04%)＞香附子Cyperus rotundus(1.08%)＞红花酢浆草Oxalis corymbosa(1.04%),其中一年生早熟禾、白茅和狗牙根为优势种,白三叶、水蜈蚣、香附子和酢浆草为亚优势种.在对春城高尔夫球场主要杂草危害情况分析的基础上,提出南方草坪杂草的综合防治建议.     

两狗牙根品种对干旱胁迫反应的差异

在新疆农业大学试验场,通过人为控水和长期自然干旱的环境下,对成坪草坪草新农一号狗牙根和喀什狗牙根进行了形态观测,同时测定了细胞膜相对透性、叶片水分饱和亏缺(WSD)、可溶性糖含量、游离脯氨酸(Pro)含量、淀粉含量、超氧化物歧化酶(SOD)活性、丙二醛(MDA)含量等若干生理生化指标。结果表明,在干旱胁迫下(0~60 d),新农一号狗牙根比喀什狗牙根叶片枯黄发生率高(4.3%~75.2%),膜系统受伤害程度大(超过30%),维持MDA/SOD平衡能力低(0.61~3.38),形态适应性较弱。但在渗透调节物质对干旱的调节能力上,比喀什狗牙根强。不同部位受害程度的大小为叶<茎<根茎<须根。     

常温贮藏下新农1号狗牙根种子劣变的研究

对常温贮藏下新农1号狗牙根Cynodon dactylon cv.Xinnong No.1种子劣变进行研究,结果表明:随贮藏年限增加,新农1号狗牙根种子的发芽指数(GI)、发芽势(GE)、活力指数(Ⅵ)、发芽率(G)、电导率及可溶性糖均表现先逐渐增大,达到最大值时下降的趋势;经相关分析,种子发芽指数、发芽率、活力指数三者间呈显著相关,可以衡量种子的老化程度,而电导率与种子的老化程度相关不显著;综合各项指标,新农1号狗牙根的贮藏年限最好不要超出4年,以2～3年最好.     

壳聚糖对狗牙根种子萌发的影响

用不同浓度的壳聚糖柠檬酸溶液处理狗牙根Cynodon dactylon种子,研究壳聚糖对狗牙根种子萌发的影响.结果表明:适当浓度的壳聚糖溶液(2.0%)能提高狗牙根种子活力,促进幼苗生长,提高发芽率和发芽势,呼吸速率也随浓度的增大而明显提高.因此壳聚糖处理有利于狗牙根种子的萌发.     

使它隆对几种草坪草生理特性的影响

通过对狗牙根Cynodon dactylon,杂交狗牙根C.dactylon ×C. transvaalensis品种Tifgreen(328)、Tifway(419)、Tifdwaf以及海雀稗Paspalum vaginatum,两耳草P.conjugatum,百喜草P.notatum,地毯草Axonopus compressus,类地毯草A.affinis,金叶钝叶草Stenotaphrum secundatum,竹节草Chrysopogon aciculatus,假俭草Eremochloa ophiuroides,匍匐剪股颖粤选1号Agrostis stolonifera cv. Yuexuan No.1新品系叶面喷施使它隆溶液,测定了部分生理指标.结果表明,使它隆对百喜草安全,0.1%使它隆溶液可用于狗牙根、海雀稗、两耳草、金叶钝叶草及假俭草草坪;高浓度使它隆总体上使草坪草叶片叶绿素含量降低、膜透性增加、可溶性糖和可溶性蛋白含量增加.     

狗牙根种质对冷害的生理反应

对采自佛山市的3个狗牙根材料(狗牙根1号,3号和5号)及杂交狗牙根品种天堂419的抗寒性进行了比较研究,发现田间种植的狗牙根材料在受到2004年12月的寒潮袭击后,相对电导率升高,其中天堂419的升高幅度最大,而狗牙根1号和5号的升高幅度较小;天堂419的光合速率降低最多,而狗牙根5号的光合速率仅轻微降低;叶片的可溶性糖含量均提高,狗牙根5号的根系可溶性糖含量升高,但其他材料的可溶性糖含量降低。在韶光地区霜冻条件下的试验结果表明,狗牙根5号的草坪质量评分最高,绿期最长,表明狗牙根5号的抗寒性较强。     

Effect of method of applying fibrolytic enzymes or ammonia to Bermudagrass hay on feed intake, digestion, and growth of beef steers

This study examined how different methods of applying a fibrolytic enzyme or ammonia affect the nutritive value of Bermudagrass hay and the performance of beef cattle. Fifty Angus x Brangus crossbred steers (mean initial BW 244 +/- 26 kg) were individually fed for ad libitum intake of a 5-wk regrowth of a mixture of Florakirk and Tifton 44 Bermudagrass [Cynodon dactylon (L.) Pers] hay for 84 d with a concentrate supplement (77% soybean hull pellets, 23% cottonseed meal (DM basis) fed at 1% of BW daily. The Bermudagrass was conserved as hay without treatment (control), with NH(3) (30 g/kg of DM), or with a fibrolytic enzyme (16.5 g/t, air-dry basis) that was applied immediately after cutting (Ec), at baling (Eb), or at feeding. Chromic oxide was dosed to steers for 10 consecutive days, and fecal Cr concentrations from the last 5 d were used to estimate apparent total tract digestibility. In situ ruminal DM degradability was measured by incubating ground (4-mm) hay samples in duplicate in each of 2 ruminally cannulated cows having ad libitum access to Bermudagrass hay and 500 g/d of soybean meal. Unlike the enzyme treatment, ammoniation increased (P < 0.001) the CP concentration and reduced (P < 0.001) NDF, hemicellulose, and lignin concentrations of hay. Total DMI was greater (P < 0.05) for steers fed hays treated with Ec or NH(3) than for those fed control hays. All additive treatments increased (P < 0.05) DM digestibility, and NH(3), Ec, and Eb treatments also increased (P < 0.01) NDF digestibility. The initial and final BW, ADG, BCS, G:F, and hip height of the steers were not affected (P > 0.05) by treatment. The wash loss fractions in hays treated with Ec and Eb were lower than that in the control hay, but the potentially degradable fraction, total degradable fraction, and the effective degradability were increased (P < 0.01) by NH(3) treatment. Application at cutting was the most promising method of enzyme treatment, and this treatment was almost as effective as ammonia for enhancing forage quality.     

Effect of ovulatory follicle size and expression of estrus on progesterone secretion in beef cows

Induced ovulation of small dominant follicles (SF, < 12 mm; CO-Synch protocol) in postpartum beef cows resulted in formation of corpora lutea (CL) that exhibited a delayed rise in progesterone (P4) compared with CL from large dominant follicles (LF, > 12 mm). Experiment 1 characterized P4 concentrations from ovulation to subsequent estrus among GnRH-induced or spontaneously ovulated SF (or= 12 mm) to determine if P4 secretion by CL formed from GnRH-induced SF remains lower postovulation in nonlactating beef cows. Nonlactating beef cows were induced to ovulate 48 h after PGF(2alpha) (CO-Synch; GnRH on d - 9, PGF(2alpha) on d - 2, and GnRH on d 0) or exhibited estrus and spontaneously ovulated after PGF(2alpha). Follicle size was measured at the second GnRH in cows induced to ovulate or approximately 3 h after the onset of estrus for cows that ovulated spontaneously. Cows were classified into 1 of 4 groups: 1) GnRH-induced ovulation-SF (or= 12 mm; Ind-LF; n = 16); 3) spontaneous ovulation-SF (or= 12 mm; Spon-LF; n = 22). Serum concentrations of P4 from d 3 to 15 were reduced in the Ind-SF compared with the Ind-LF (P = 0.05), Spon-SF (P = 0.07), and Spon-LF (P = 0.03). Experiment 2 characterized P4 concentrations (0 to 60 d postAI) among GnRH-induced or spontaneously ovulated SF (or= 13 mm) to determine if P4 secretion by CL formed from GnRH-induced SF remained lower during early gestation. Ovulation was induced with GnRH 48 h after PGF(2) (CO-Synch) or occurred spontaneously, and ovulatory follicle size was measured at AI. Lactating cows were classified into 1 of 3 groups: 1) GnRH-induced ovulation-SF (or= 13 mm; Ind-LF; n = 43); or 3) spontaneous ovulation-LF (>or= 13 mm; Spon-LF; n = 27). The increase in P4 concentrations was greater (P = 0.06) in pregnant (d 2 to 12) compared with nonpregnant cows. Also, the increase in P4 from d 2 to 12 was greater (P = 0.01) in the Ind-LF compared with the Ind-SF groups, but there was no difference (P = 0.94) among groups in P4 from d 14 to 60 in pregnant cows. Follicle size at AI influenced the increase in P4 in cows that failed to conceive (P = 0.007), but not among cows that became pregnant (P = 0.32) to AI. In summary, P4 secretion after GnRH-induced ovulation of SF was decreased from d 2 to 12 compared with that of LF, but was similar among pregnant cows from d 14 to 60 postAI (d 0).     

Effect of short chain fatty acids infused intraileally on interdigestive exocrine pancreatic secretions in growing pigs

The effect of intraileally infused short chain fatty acids (SCFA) and saline as control on the exocrine pancreatic secretions during the interdigestive phase was studied using three 8-weeks-old piglets. Pigs were surgically fitted with a pancreatic duct catheter, re-entrant duodenal T-cannula for collection and subsequent return of pancreatic juice, and with an infusion T-cannula at the distal ileum. Saline as control, 5.0 and 10.0 mm butyrate, 7.5 and 15.0 mm propionate and 85.0 and 170.0 mm acetate were infused at 2 ml/kg body weight (BW) for 30 min into the ileum of overnight fasted piglets via ileal T-cannula. The calculated volume of infusates was administrated in five equal bolus at 6 min intervals over a period of 30 min. The pancreatic juice was collected 60 and 30 min before and 30, 60, 90 and 120 min after the start of infusion. The trypsin (p = 0.07, p > 0.15 respectively) and protein (p > 0.15, p = 0.05 respectively) outputs immediately decreased after the infusion of acetate at the dose of 85.0 and 170.0 mm, respectively, whereas pancreatic juice outflow (p > 0.15) was not significantly affected when compared with levels 30 min before infusion. After the infusion of butyrate at the dose of 5.0 mm, trypsin (p = 0.01) and protein (p = 0.12) outputs increased immediately whereas pancreatic juice outflow was not affected (p > 0.15) in comparison with levels 30 min before infusion. No significant differences were observed after infusion of butyrate at the dose of 10 mm for the pancreatic juice outflow, trypsin and protein outputs when compared with the level before infusion, although these values were numerically lower immediately after the infusion. The pancreatic juice outflow increased (p = 0.03) after the infusion of propionate at the dose of 7.5 mm and decreased (p = 0.005) immediately after the infusion of propionate at the dose of 15.0 mm when compared with the levels 30 min before the infusions. After the infusion of propionate at the dose of 7.5 or 15.0 mm for the output of protein and trypsin, no significant differences (p > 0.15) were observed when compared with levels 30 min before infusion. In summary, the intraileal infusion of SCFA at different doses exerts a short-term and moderate effect on the interdigestive exocrine pancreatic secretions in pigs.     

Endocrine factors and ovarian follicles are influenced by body condition and somatotropin in postpartum beef cows

Multiparous beef (1/4 to 3/8 Bos indicus; n = 99) cows were managed to achieve low (BCS = 4.3 +/- 0.1; n = 50) or moderate (BCS = 6.1 +/- 0.1; n = 49) body condition (BC) to determine the influence of bovine (b) ST on the number of follicles, diameter of largest follicle, and serum concentrations of IGF-I, triiodothy-ronine (T3), thyroxine (T4), and prolactin. Beginning 32 d postpartum, cows within each BC were assigned randomly to treatment with or without bST. Non-bST-treated cows received no treatment, and treated cows were administered bST (Posilac, 500 mg, s.c.) on d 32, 46, and 60 postpartum. On d 60, all cows received a controlled internal drug-releasing (CIDR) device for 7 d and PGF(2alpha) at CIDR removal (CIDR-PGF(2alpha)). Blood samples (7 mL) were collected at each bST treatment and d 39 and 67 postpartum. Ultrasound was performed 1 d after CIDR-PGF(2alpha) to determine the number of small (2 to 9 mm) and large (>/=10 mm) follicles and the diameter of largest follicle. Cows treated with bST in low BC had increased (P < 0.05) IGF-I vs. low-BC non-bST-treated cows on d 39, 46, 60, and 67 postpartum. Prolactin and T3 were greater (P < 0.05) in moderate-BC than in low-BC cows on all sample dates. Thyroxine was greater (P < 0.001) in moderate-BC cows on d 46, 60, and 67 compared with low-BC cows. On d 67, bST-treated cows had greater (P < 0.05) T4 compared with non-bST-treated cows. Diameter of the largest follicle 1 d after CIDR-PGF(2alpha) was greater (P < 0.01) in anestrous cows treated with bST than for non-bST-treated anestrous cows. Diameter of the largest follicle was correlated with concentrations of IGF-I (r >/= 0.18; P /= 0.17; P /= 0.20; P 相似文献   

Clinical and ultrasonographic findings in the mammary gland of sheep

AIM: To compare clinical and ultrasonographic findings and assess the value of ultrasonography for evaluating the structure and condition of the teat and teat canal of sheep. METHODS: The mammary glands of 30 lactating ewes were examined clinically and using ultrasonography. The distance from the teat tip to the ground was measured and diagnostic images of the body of the gland, gland cistern and teat cistern were obtained using an 8.5 MHz frequency ultrasonic transducer. A California mastitis test (CMT) and bacteriological culture were performed on milk samples collected from each half of each udder. RESULTS: Udder parenchyma and teats were palpably normal in 27/30 (90%) ewes. Milk clots or abnormalities were evident in 4/30 (13%) udders, lesions in the glandular parenchyma and/or teats were evident by palpation in 3/30 (10%), and pathogenic bacteria were cultured from 2/30 (7%). In both of the latter cases, mastitis was diagnosed based on clotted and discoloured appearance of milk and highly positive CMT reactions. Ultrasonographic examination in these udders revealed non-homogenous regions in the glandular tissue and alternating areas of hyperechogenic and hypoechogenic tissue. Overall, highly positive CMT reactions were evident in milk from 14/30 (47%) left halves and 9/30 (30%) right halves (p=0.02). No relationship between teat-to-ground distances and CMT results was evident (p>0.05). Teat canal lengths ranged from 5.7-10.3 mm (mean=8.6; SD=1.3 mm) and the widths from 1.8-3.1 mm (mean=2.3; SD=0.4 mm). Milk sampled from ewes that had long (> or = 9 mm) or wide (> or = 2 mm) teat canals was highly positive to the CMT in 75% and 83% of cases, respectively. CONCLUSIONS: Ultrasonographic measurements of the length and width of the teat canal appeared to correlate with CMT results. The use of ultrasonography in evaluating the health of the udder of small ruminants holds promise for the future.     

Effects of inorganic and organic copper supplemented to first-calf cows on cow reproduction and calf health and performance

Two experiments were conducted to determine whether the supplementation of Cu in the organic or inorganic form to 2-yr-old cows, before and after calving, affects reproduction rate, calf health and performance, passive transfer of immunoglobulin, or liver and serum Cu concentrations compared with unsupplemented controls. Cows (n = 75 in 1997; n = 120 in 1998) were randomly assigned by estimated calving date and body condition score to one of three treatments: 1) Control, control; 2) Inorganic, inorganic Cu supplement (200 mg Cu from CuSO4); 3) Organic, organic Cu supplement (100 mg Cu from AvailaCu). In 1998, a fourth treatment was added; 4) CU-ZN, organic Cu and Zn (400 mg Zn from AvailaZn in the Organic diet). Cows were fed a hay-based diet and individually fed supplements for approximately 45 d before and 60 d after calving (approximately January 15 to May 15 each year). Liver biopsies were obtained from cows before supplementation began, and from cows and calves at 10 and 30 d after calving. Blood samples were obtained from both cows and calves at calving, and colostrum samples were collected for IgG and mineral content. Cow liver Cu concentrations before supplementation began were 58 mg/kg in 1997 and 40 mg/kg (DM basis) in 1998. By 10 d after calving, liver Cu concentrations of Control cows had decreased (P < 0.05) to 24 mg/kg (Cu deficient) in both years, whereas liver Cu concentrations of Cu-supplemented cows increased (P < 0.05) in both years. Calf liver Cu concentrations at 10 d of age were similar (P > 0.10) for all treatment groups. No differences (P > 0.10) were found in colostrum Cu concentrations, or in calf health among treatments. No differences (P > 0.10) were found in cow BW change, calf serum Cu concentrations, calf weaning weights, or in cow 60-d pregnancy rates among treatments in either year. In 1998, cows in the Organic group had higher (P < 0.05) 30-d pregnancy rate than Control cows. Neither serum samples nor placental tissue were reliable indicators of Cu status in cows. Feeding supplemental Cu (either inorganic, organic, or organic with extra Zn) to cows with liver Cu concentrations of approximately 50 mg/kg before calving did not improve cow 60-d pregnancy rates or the health and performance of their calves when compared with unsupplemented cows.     

两种暖季型草坪草优良品种耐践踏性评价

采用模拟践踏处理的方法对8个狗牙根(Cynodon)品种和4个结缕草(Zoysia)品种的耐践踏性进行初步评价。结果表明,践踏处理对各参试品种的坪用价值指标造成了显著影响(P0.05),践踏处理之后各材料叶片变窄变薄,密度、盖度、均一性下降,叶色变浅,反弹率升高,践踏处理1~2个月对参试材料直立生长影响较小,而处理3个月后草层高度显著下降。不同材料的耐践踏性存在较大差异,在短期践踏条件下,8个狗牙根品种中阳江狗牙根和C29100M1的坪用价值显著优于其他材料,而在长期践踏处理下,苏植2号杂交狗牙根坪用价值最高。4个结缕草品种中,苏植1号杂交结缕草作为运动草坪的综合坪用质量最高。该研究为这些新品种进一步的开发利用提供参考依据。     

Urea metabolism in beef steers grazing Bermudagrass, Caucasian bluestem, or gamagrass pastures varying in plant morphology, protein content, and protein composition

Pastures of Bermudagrass (Cynodon dactylon, BG), Caucasian bluestem (Bothriochloa caucasica, CBS), and gamagrass (Tripsacum dactyloides, GG) were evaluated from the perspectives of forage composition, selection during grazing, and N metabolism in beef steers. All pastures were fertilized with 78 kg/ha of N approximately 60 and 30 d before sample collection. In 2000 and 2001, 12 steers (250 kg of BW) were blocked based on BW and then assigned randomly to a replicated, randomized complete block design, with 2 pastures of each forage and 2 steers per pasture. Three other steers with esophageal fistulas were used to collect masticate samples to represent intake preferences. Herbage mass was >1,900 kg/ha. After at least 14 d of adaptation, urine and blood samples were collected for determination of serum urea N and percentage of urinary N in the form of urea. One steer per pasture (6 steers per year) was infused i.v. with (15,15)N urea for 50 h before collecting urine for 6 h to measure urea N enrichment, urea entry rate, urinary urea excretion, gut urea recycling, and return of urea N to the ornithine cycle. The canopy leaf:stem DM ratio differed (P = 0.01) among BG (0.50), CBS (1.01), and GG (4.00). Caucasian bluestem had less CP (% of DM) than GG or BG in the canopy (9.6 vs. 12.0 or 12.3, P = 0.07) and in the masticate (9.8 vs. 14.7 or 13.9, P = 0.04). Bermudagrass had less true protein (% of CP) than CBS or GG in the canopy (72.9 vs. 83.3 or 83.0, P = 0.07) and in the masticate (73.7 vs. 85.8 or 88.0, P = 0.04). Compared with GG and BG, CBS had less serum urea N (10.1 or 12.2 vs. 2.5 mM, P = 0.01), urea entry rate (353 or 391 vs. 209 mmol of N/h, P = 0.07), and urinary urea excretion (105 or 95 vs. 18 mmol of N/h, P = 0.04), and a greater return of urea N to the ornithine cycle as a proportion of gut urea recycling (0.109 or 0.118 vs. 0.231, P = 0.02). Urea production and recycling in these steers responded more to the N concentration in the grasses than to differences in plant protein fractions. There was no evidence of improved N capture by the steers due to changes in the leaf:stem ratio among the grasses at the herbage mass evaluated.