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1.
The allelopathic water extracts (AWEs) may help improve the tolerance of crop plants against abiotic stresses owing to the presence of the secondary metabolites (i.e., allelochemicals). We conducted four independent experiments to evaluate the influence of exogenous application of AWEs (applied through seed priming or foliage spray) in improving the terminal heat and drought tolerance in bread wheat. In all the experiments, two wheat cultivars, viz. Mairaj‐2008 (drought and heat tolerant) and Faisalabad‐2008 (drought and heat sensitive), were raised in pots. Both wheat cultivars were raised under ambient conditions in the wire house till leaf boot stage (booting) by maintaining the pots at 75% water‐holding capacity (WHC). Then, managed drought and heat stresses were imposed by maintaining the pots at 35% WHC, or shifting the pots inside the glass canopies (at 75% WHC), at booting, anthesis and the grain filling stages. Drought stress reduced the grain yield of wheat by 39%–49%. Foliar application of AWEs improved the grain yield of wheat by 26%–31%, while seed priming with AWEs improved the grain yield by 18%–26%, respectively, than drought stress. Terminal heat stress reduced the grain yield of wheat by 38%. Seed priming with AWEs improved the grain yield by 21%–27%; while foliar application of AWEs improved the grain yield by 25%–29% than the heat stress treatment. In conclusion, the exogenous application of AWEs improved the stay green, accumulation of proline, soluble phenolics and glycine betaine, which helped to stabilize the biological membranes and improved the tolerance against terminal drought and heat stresses.  相似文献   
2.
Summary Rapid drying of surface layers of coarse-textured soils early in the growth season increases soil strength and restricts root growth. This constraint on root growth may be countered by deep tillage and/or early irrigation. We investigated tillage and irrigation effects on root growth, water use, dry matter and grain yield of wheat on loamy sand and sandy loam soils for three years. Treatments included all combinations of two tillage systems i) conventional tillage (CT) — stirring the soil to 10 cm depth, ii) deep tillage (DT) — subsoiling with a single-tine chisel down to 35–40 cm, 40 cm apart followed by CT; and four irrigation regimes, i) I0 — no post-seeding irrigation, ii) I1 — 50 mm irrigation 30 days after seeding (DAS), iii) I2 — 50 mm irrigation 30 DAS and subsequent irrigations of 75 mm each when net evaporation from USWB class A open pan (PAN-E) since previous irrigation accumulated to 82 mm, and iv) I3 — same as in I2 but irrigation applied when PAN-E accumulated to 62 mm. The crop of wheat (Triticum aestivum L. HD 2329) was fertilized with 20kg P, 10kg K and 5kg Zn ha–1 at seeding. The rate of nitrogen fertilization was 60 kg ha–1 in the unirrigated and 120 kg ha–1 in the irrigated treatments. Tillage decreased soil strength and so did the early post-seeding irrigation. Both deep tillage and early irrigation shortened the time needed for the root system to reach a specified depth. Subsequent wetting through rain/irrigation reduced the rate of root penetration down the profile and also negated deep tillage effects on rooting depth. However, tillage/irrigation increased root length density in the rooted profile even in a wet year. Better rooting resulted in greater profile water depletion, more favourable plant water status and higher dry matter and grain yields. In a dry year, the wheat in the DT plots used 46 mm more water, remained 3.3 °C cooler at grain-fill and yielded 68% more grain than in CT when unirrigated and grown in the loamy sand. Early irrigation also increased profile water depletion, more so in CT than DT. Averaged over three years, grain yield in DT was 12 and 9% higher than in CT on loamy sand and sandy loam, respectively. Benefits of DT decreased with increase in rainfall and irrigation. Irrigation significantly increased grain yield on both soils, but the response was greatly influenced by soil type, tillage system and year. The study shows that soil related constraints on root growth may be alleviated through deep tillage and/or early irrigation.  相似文献   
3.
A field study was conducted to investigate the influence of variable rates of application of N and P fertilizers in splits at various times on the growth and the seed and oil yields of canola (Brassica napus L.) during 1995–97. Rates of fertilizer application were 0 and 0 (F0), 60 and 0 (F1), 0 and 30 (F2), 60 and 30 (F3), 90 and 60 (F4) and 120 and 90 (F5) kg N ha?1 and kg P2O5 ha?1. All the P was applied at sowing while N was applied in splits, i.e. all at sowing, half at sowing and half with first irrigation, or half at sowing and half at flowering. The responses of growth, seed yield and components of yield were consistent in both years. Increasing the rate of fertilizer application from F4 (90/60 kg N/P2O5 ha?1) to F5 (120/90 kg N/P2O5 ha?1) increased the leaf area index (LAI) relative to the control and to lower rates of fertilizer application. For both crops, application of 90/60 kg N/P2O5 ha?1 significantly enhanced total dry matter (TDM) and seed yield. Seed yield increased mainly due to a greater number of pods per plant and seeds per seed‐pod. The time of fertilizer application did not significantly affect seed yield or components of yield in either season. Oil yield generally followed seed yield, increasing with increasing rate of fertilizer application up to 90/60 kg N/P2O5 ha?1. The maximum oil contents were obtained from the control. The results show that seed and oil yields of canola were maximized at the F4 (90/60 kg N/P2O5 ha?1) rate of application under the agro‐ecological conditions of Faisalabad, Pakistan.  相似文献   
4.
5.
The impact of soil (1, 2 kg ha?1) and foliar (100, 200 mg L?1) boron (B) with control (no B) was evaluated on phenology and yield formation of Camelina each applied at stem elongation and flowering stages. Foliar (200 mg L?1) or soil B (2 kg ha?1) resulted in earlier flowering and maturity, increased fruit bearing branches (19.68%), number of siliqua, seeds per siliqua (4.6%), biological yield (15%), seed yield (24%), harvest index (11.4%) and oil contents (23%) than no B. Increased fruit bearing branches, seed filled siliqua or seed numbers, harvest index and oil quality can be attributed to changes in dry matter accumulated of stem with simultaneous increase in siliqua dry weight with foliar or soil applied B. In crux, foliar (200 mg L?1) or soil applied (2 kg ha?1) B seems promising to improve seed and oil yield, harvest index of Camelina sativa under B deficient condition.  相似文献   
6.
Besnoitia cysts and lesions were observed in the skin, blood vessels, epididymis and testes of two wild goats (Capra aegagrus) and in the subcutaneous tissues of two domestic goats (Capra hircus) in the Fars Province of Iran. The seminiferous tubules in the wild goats showed aspermatogenesis, degeneration and atrophy of germinal epithelium.  相似文献   
7.
8.
Glanders is a highly infectious and zoonotic disease of solipeds caused by Burkholderia mallei. Progressive loss of efficiency and fatal outcome resulted in massive economic losses, which forced veterinary authorities throughout the world to implement disease control measures; these measures included mass testing using the complement fixation test and/or malleinization, and the culling of positives. This led to the eradication of glanders from Western Europe and North America in the 1950s. However, in the last decade, the number of outbreaks in Asia and South America increased steadily, and glanders regained the status of a re-emerging transboundary disease. Pakistan has been an endemic country for the past 120 years, but concise data on the presence of disease are not available. A total of 533 serum samples were collected from draught equines, a suspected risk group for glanders, from various districts of Punjab in Pakistan. The complement fixation test and the highly sensitive Western blot technique were used for serodiagnosis. No animal (horse, mule, and donkey) was found to be positive for infection. Glanders seems to be restricted to remote, sporadic pockets of endemicity and may cause outbreaks after being introduced into naive populations by (asymptomatic) shedders.  相似文献   
9.

Relationship of scrotal bifurcation or splitness with breeding soundness traits was investigated in 15 Beetal bucks (17–20 months of age and 48.72?±?1.57 kg mean BW). Breeding soundness traits of conjoined/unsplit (n?=?6) scrotal bucks was compared with split (n?=?9) scrotal bucks having lengthwise >?1 in. bifurcation. Two consecutive semen ejaculations per buck were collected at monthly interval during summer season (April to June 2018) using intact buck as teaser and sexual behavior was simultaneously recorded. Scrotal morphometry parameters, i.e., scrotal circumference, scrotal volume, scrotal skin thickness, testis length, width, and thickness were also recorded. Bucks with split scrotum had relatively more scrotal dimensions (scrotal circumference (P?<?0.01), scrotal volume (P?<?0.01), testis length (P?<?0.01)) than conjoined scrotal bucks. Among various semen attributes, semen volume of first ejaculate (P?<?0.01), second ejaculate (P?<?0.05), mean semen volume (P?<?0.01), total sperm count of first ejaculate, and mean sperm count of both ejaculates were more (P?<?0.01) in split scrotal bucks. However, scrotal bifurcation had no influence on sexual behavior of bucks. It is concluded that Beetal bucks with split scrotum had relatively better breeding efficiency traits than conjoined scrotal bucks.

  相似文献   
10.
Rice performance under drought stress is mainly impeded by oxidative damage and hampered plant water status, which may be improved by exogenous use of osmoprotectants. In this study, the role of glycinebetaine (GB) to improve drought tolerance in rice (Oryza sativa L.) cultivar Super-basmati was evaluated. GB was used both as seed and foliar application. For priming, seeds were soaked in 50, 100 and 150 mg l−1 aerated solution of GB for 48 h. At four-leaf stage, one set of plants was subjected to drought stress, while the other set kept at full field capacity. Drought was maintained at 50 % of field capacity by watering when needed. For exogenous application, 50, 100 and 150 mg l−1 GB levels were applied at five-leaf stage. Drought stress greatly reduced the rice growth while GB application improved it both under well-watered and drought conditions. Drought tolerance in rice was strongly related to the maintenance of tissue water potential and antioxidant system, which improved the integrity of cellular membranes and enabled the plant to maintain high photosynthesis. Foliar treatments were more effective than the seed treatments, while among the GB treatment, foliar application with 100 mg l−1 was the most effective.  相似文献   
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