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31.
Teichmann T Bolu-Arianto WH Olbrich A Langenfeld-Heyser R Göbel C Grzeganek P Feussner I Hänsch R Polle A 《Tree physiology》2008,28(9):1305-1315
GH3 genes related to the auxin-inducible Glycine max (L.) Merr. GmGH3 gene encode enzymes that conjugate amino acids to auxin. To investigate the role of GH3 enzymes in stress responses and normal wood development, Populus x canescens (Ait.) was transformed with the promoter-reporter construct GH3::GUS containing a GH3 promoter and the 5' UTR from soybean. beta-Glucuronidase (GUS) activity was present in the vascular tissues of leaves and in developing lateral roots and was inducible in silent tissues by external auxin application. A decrease in GUS activity from the stem apex to the bottom corresponded to decreases in auxin concentrations in these tissues. High auxin concentration and high GH3::GUS activity were present in the pith tissue, which may provide storage for auxin compounds. GH3 reporter was active in ray cells, paratracheal parenchyma cells, maturing vessels and in cells surrounding maturing phloem fibers but not in the cambium and immature phloem, despite high auxin concentrations in the latter tissues. However, the GH3 promoter in these tissues became active when the plants were exposed to abiotic stresses, like bending or salinity, causing changes in wood anatomy. We suggest that adjustment of the internal auxin balance in wood in response to environmental cues involves GH3 auxin conjugate synthases. 相似文献
32.
Effect of NaCl on growth and ion relations in two salt-tolerant strains of Paxillus involutus 总被引:1,自引:0,他引:1
Hua Zhang Jing Li Shao-liang Chen Cun-fu Lu Rui-gang Wang Song-xiang Dai Hui-juan Zhu Yun-xia Zhang Yong Shi Mei-juan Wang Yan-jun Lu Li-si Li Rosemarie Langenfeld-Heyser Fritz Eberhard Andrea Polle 《中国林学(英文版)》2008,10(2):95-100
The effect of NaCl on growth, biomass and ion relations of two salt-tolerant isolates of Paxillus involutus, MAJ and NAU were investigated. The two Paxillus strains were exposed to the following concentrations of NaCl: 0, 100, 200 and 500 mmol·L^-1. Growth of MAJ and NAU was enhanced by 100 mmol·L^-1 NaCl but severely inhibited at the concentration of 500 mmol·L^-1. NAU exhibited a greater capacity to exclude Na^+ and Cl^- under all salinity levels, whereas the salt-includer MAJ had a higher capacity in nutrient uptake under salt stress. The ratios Na^+/K^+, Na^+/Ca^2+ and Na^+/Mg^2+ in NaCl-treated MAJ and NAU did not increase at levels of 100 and 200 mmol·L^-1 NaCl but markedly increased at 500 mmol·L^-1. This suggests that the two strains, especially MAJ, enhanced nutrient uptake corresponding to the increased Na^+ influx at moderate salinity. We conclude that both MAJ and NAU are able to tolerate 500 mmol·L^-1 NaCl but there are species-specific differences in retaining ionic homeostasis in the two Paxillus strains. NAU is a salt-excluder, MAJ is a salt-includer but retains a high capacity in nutrient selectivity under saline conditions. Their definite mechanisms to enhance salt tolerance of mycorrhizal hosts need further study. 相似文献
33.
Tedeschi LO Boin C Fox DG Leme PR Alleoni GF Lanna DP 《Journal of animal science》2002,80(6):1671-1682
Data from three comparative slaughter experiments with individually fed Nellore bulls (n = 31) and steers (n = 66) were utilized to determine their NEm and NEg requirements when fed high-forage diets. The experimental design provided ranges in ME intake, BW, and ADG for the development of regression equations to predict NEm and NEg requirements. The Nellore bulls (Trial 1) were divided into two intake levels (ad libitum and 65% of the ad libitum). The steers (Trials 2 and 3) were allocated to three intake levels (ad libitum and 55 and 70% of the ad libitum). In both trials, there were three slaughter groups within each intake level. The three end points for the bulls were different days on treatment (100, 150, and 190 d and 130, 180, and 200 d, respectively, for older and younger animal subgroups). The steers were slaughtered when animals of the ad libitum treatment reached 400, 440, and 480 kg shrunk BW (SBW) on average for the first, second, and third group, respectively. For all body composition determinations, whole empty body components were weighed, ground, and subsampled for chemical analysis. In each of the trials, initial body composition was determined with equations developed from a baseline slaughter group, using SBW and empty BW (EBW), fat (EBF), and protein (EBP) as variables. The NEm was similar for bulls and steers; NEm averaged 77.2 kcal/ kg0.75 EBW. However, the efficiency of conversion of ME to net energy for maintenance was greater for steers than for bulls (68.8 and 65.6%, respectively), indicating that bulls had a greater ME requirement for maintenance than steers (5.4%; P < 0.05). Our analyses do not support the NRC (2000) conclusion that Nellore, a Bos indicus breed, has a lower net energy requirement for maintenance than Bos taurus breeds. An equation developed with the pooled data to predict retained energy (RE) was similar to the NRC (2000) equation. A second equation was developed to predict RE adjusted for degree of maturity (u): RE = (6.45 - 2.58/u) x EWG x e(0.469) x u), where u = current EBW/final EBW in which final EBW was 365 kg for steers and younger bulls and 456 kg for older bulls at 22% EBF, respectively. 相似文献
34.
Chay-Canul AJ Ayala-Burgos AJ Ku-Vera JC Magaña-Monforte JG Tedeschi LO 《Tropical animal health and production》2011,43(5):929-936
The objective of this work was to evaluate the effect of metabolizable energy intake (MEI) on changes in fat depots of adult
Pelibuey ewes fed roughage diets under tropical conditions. Eighteen 3-year-old Pelibuey ewes with similar body weight (BW)
of 37.6 ± 4.0 kg and body condition score (BCS) of 2.5 ± 0.20 were randomly assigned to three groups of six ewes each in a
completely randomized design. Ewes were housed in metabolic crates and fed three levels of MEI: low (L), medium (M), and high
(H) for 65 days to achieve different BW and BCS. At the end of the experiment, the ewes were slaughtered. Data recorded at
slaughter were: weights of viscera and carcass. Internal fat (IF, internal adipose tissue) was dissected, weighed, and grouped
as pelvic (around kidneys and pelvic region), omental, and mesenteric regions. Carcass was split at the dorsal midline in
two equal halves, weighed, and chilled at 6°C during 24 h. After refrigeration, the left half of the carcass was completely
dissected into subcutaneous and intermuscular fat (carcass fat). Dissected carcass fat (CF) of the left carcass was adjusted
as whole carcass. At low levels of MEI, proportion of IF and CF was approximately 50%; however, as the MEI was increased,
the proportion of IF was increased up to 57% and 60% for M and H, respectively. Omental and pelvic fat depots were those which
increased in a larger proportion with respect to the mesenteric fat depot. Regression equations between the weight of each
body fat depot and BW had a coefficient of determination (r
2) that ranged between 0.37 for mesenteric fat and 0.87 for CF. The regression with BCS had a r
2 that ranged between 0.57 for mesenteric and 0.71 for TBF. BW was the best predictor for TBF, CF, omental fat, and pelvic
fat; whereas, BCS was better than BW in predicting IF and mesenteric fat. Inclusion of both BW and BCS in multiple regressions
improved the prediction for all fat depots, except for pelvic fat, which was best estimated by BCS alone. The greater slope
of the regression for the pelvic fat depot equation, relative to TBF (1.40), EBW (4.02), and BCS (2.36), suggested that pelvic
fat has a greater capacity to accumulate and mobilize fat. These results indicated that adult Pelibuey ewes seem to store
a considerable proportion of absorbed energy in the IF depots rather than in the carcass. 相似文献
35.
Carcass traits have been successfully used to determine body composition of steers. Body composition, in turn, has been used to predict energy content of ADG to compute feed requirements of individual animals fed in groups. This information is used in the Cornell value discovery system (CVDS) to predict DM required (DMR) for the observed animal performance. In this experiment, the prediction of individual DMR for the observed performance of group-fed yearling bulls was evaluated using energy content of gain, which was based on ultrasound measurements to estimate carcass traits and energy content of ADG. One hundred eighteen spring-born purebred and crossbred bulls (BW = 288 +/- 4.3 kg) were sorted visually into 3 marketing groups based on estimated days to reach USDA low Choice quality grade. The bulls were fed a common high-concentrate diet in 12 slatted-floor pens (9 to 10 head/pen). Ultrasound measurements including back-fat (uBF), rump fat, LM area (uLMA), and intramuscular fat were taken at approximately 1 yr of age. Carcass measurements including HCW, backfat over the 12th to 13th rib (BF), marbling score (MRB), and LM area (LMA) were collected for comparison with ultrasound data for predicting carcass composition. The 9th to 11th-rib section was removed and dissected into soft tissue and bone for determination of chemical composition, which was used to predict carcass fat and empty body fat (EBF). The predicted EBF averaged 23.7 +/- 4.0%. Multiple regression analysis indicated that carcass traits explained 72% of the variation in predicted EBF (EBF = 16.0583 + 5.6352 x BF + 0.01781 x HCW + 1.0486 x MRB - 0.1239 x LMA). Because carcass traits are not available on bulls intended for use as herd sires, another equation using predicted HCW (pHCW) and ultrasound measurements was developed (EBF = 39.9535 x uBF - 0.1384 x uLMA + 0.0867 x pHCW - 0.0897 x uBF x pHCW - 1.3690). This equation accounted for 62% of the variation in EBF. The use of an equation to predict EBF developed with steer composition data overpredicted the EBF predicted in these experiments (28.7 vs. 23.7%, respectively). In a validation study with 37 individually fed bulls, the use of the ultrasound-based equation in the CVDS to predict energy content of gain accounted for 60% of the variation in the observed efficiency of gain, with 1.5% bias, and identified 3 of the 4 most efficient bulls. 相似文献
36.
Studies were carried out on a population ofThrips tabaci Lindeman (Thysanoptera: Thripi-dae) from Liguria to assess its sex-ratio and its ability to transmit four tospoviruses: tomato
spotted wilt (TSWV), impatiens necrotic spot, tomato chlorotic spot and groundnut ringspot. The population was composed of
females only (therefore thelytokous). The first instar larvae were allowed to acquire the virus for 48 h on infected leaves
of datura, basil or pepper, and then reared on cucumber until emergence, which medially occurred 9.5 days after hatching.
Transmission capacity was checked using two inoculation access periods (lAPs) of 48 h each on pepper leaf disks.T. tabaci was able to transmit TSWV isolate P105 with an efficiency of 16.7% and 4.4% in the first and second IAP, respectively, and
TSWV isolate BR-01 with an efficiency of 2.0%. The onion thrips did not transmit the three other tospoviruses. During the
IAPs, almost all adults fed on the leaf disks, producing evident silvery scars. The presence of tospovirus nucleocapsids in
thrips was assayed by Triple Antibody Sandwich (TAS) and cocktail ELISA. Not all adults that had transmitted TSWV were positive
in the tests, whereas some non-transmitter individuals proved positive. For each of the other tospoviruses, some thrips were
positive in at least one test, although none was able to transmit the virus. 相似文献
37.
38.
Herlon M. Alhadas Sebastião C. Valadares Filho Luis O. Tedeschi Rizielly S. R. Vilela Gilyard A. P. Souza Bruno C. Lage Breno C. Silva Luciana N. Rennó Mario F. Paulino 《Animal Science Journal》2021,92(1):e13623
This study evaluated the effect of including low-fat dried distillers grains (DDG) on young Nellore bulls performance, nutritional parameters, and nitrogen metabolism. Thirty-five Nellore cattle were randomly divided into four diets: without dried distillers grains (D0) or with the inclusion of DDG at 150 g/kg (D150), 300 g/kg (D300), or 450 g/kg (D450). The evaluation period lasted 126 days, and three periods of collection of feces and urine were carried out. Final body weight (P = 0.099) and average daily gain (P = 0.097) tended to decrease linearly; the digestibility of dry matter (P < 0.001), organic matter (P < 0.001), ether extract (P < 0.001) and nonfiber carbohydrates (P < 0.001), and intakes of total digestible nutrients (TDN, P < 0.001) decreased linearly. The increase in crude protein intake (P < 0.001) did not result in an increase in the amount of nitrogen retained (P = 0.540). We concluded that the inclusion of low-fat DDG in finishing diets up to the level of 450 g/kg tends to reduce animal performance and the intake of TDN. 相似文献
39.
Jose Andres Guevara-Coto Natalia Barboza-Vargas Eduardo Hernandez-Jimenez Rosemarie W. Hammond Pilar Ramirez-Fonseca 《European journal of plant pathology / European Foundation for Plant Pathology》2011,131(2):167-170
Whiteflies are an insect group that comprises multiple species and biotypes, capable of affecting crops by phloem feeding,
virus transmission and promotion of fungal colonization. The distribution of these pests is worldwide. In Costa Rica, a country
located in the tropics, the most problematic whiteflies are Bemisia tabaci biotype B and Trialeurodes vaporariorum. In September 2009, two greenhouses in the Alfaro Ruiz region, northwest of the country’s capital, San Jose, were surveyed
as part of a larger effort to determine the occurrence of species and races of whiteflies in this agronomically important
region. In addition, the insect samples were analyzed to determine the presence of Tomato chlorosis virus (ToCV), a yield-affecting crinivirus transmitted by whiteflies. The results revealed the presence of the Q biotype of B. tabaci, and important invasive species, as well as the expected T. vaporariorum. Viral detection assays identified potentially viruliferous individuals for Tomato chlorosis virus. These results identified a new pest capable of harbouring plant viruses has been identified, as well as a viral agent (ToCV)
in a region where it was not reported, and which might cause significant yield losses. 相似文献
40.
Nicholas H. Dodman BVMS MRCVS DVA Linda Gray BSC Rosemarie Williams DVM Geoffrey Goldspink PHD DSC 《Journal of Equine Veterinary Science》1985,5(1):11-15
Intracompartmental muscle pressure, temperature and pH were measured in a group of 23 anesthetized horses in an attempt to elucidate the etiology of post-anesthetic lameness (PAL). The intramuscular pressure remained reasonably constant throughout anesthesia in most horses, while muscle temperature and pH fell. Five of the horses became lame after anesthesia. Two of these lame horses exhibited atypical trends in the physiological variables measured. The etiology of PAL is discussed in the lightof the results. 相似文献