Effects of Low Doses of Glyphosate on Agronomic Traits of Upland Rice

Research has shown the occurrence of the hormesis effect in some upland rice cultures resulting from low-dose application of glyphosate. Glyphosate herbicide is widely used in Brazilian agriculture for controlling the large quantity of weeds. The aim of this work was to verify the effects of low-dose application of glyphosate herbicide on agronomic characteristics in upland rice. The experimental design used was randomized blocks comprising five low-dose applications of glyphosate herbicide (10, 20, 40, 70, and 100?g acid equivalent [a.e.] ha^?1) and the control, in two stages of development of the rice culture (tillering [V4] and floral differentiation [R1]) with four repetitions. The agronomic traits of upland rice were evaluated. Data were subjected to variance analysis, polynomial regression analysis for the quantitative factor, and Tukey’s test for the qualitative factor at p?<?0.05. The grain yield and the number of spikelets per panicle increased with the application of 10?g a.e. ha^?1 of glyphosate at the floral differentiation stage. Until the low dose of 75?g a.e. ha^?1, there was an increase in the number of panicles. Low doses between 70 and 100?g a.e. ha^?1 applied in R1 provided less spikelets per panicle, lower 100-grain weight, and lower grain yield. The leaf flavonoid content increased due to the increase in the low doses of glyphosate herbicide.

     

Effect of left vs. right recumbency on the vertebral heart score in normal dogs

The effect of right vs. left recumbency on computation of the vertebral heart score (VHS) was assessed in 63 healthy dogs. The VHS was significantly higher in right lateral recumbency (9.8 +/- 0.6 vs. 9.5 +/- 0.8; P < 0.0004). Gender and dog size did not significantly influence VHS values while there was m oredifference between left and right side measurements when considering the type of thorax (P = 0.055).     

Radiographic assessment of cattle hoofs (ungulae) of the Nellore breed: Reference standards

The purpose of this work was to determine a radiographic standard of normality for lateral and medial ungulae in 3‐year‐old bovine females of the Nellore breed. Twenty‐six cows underwent radiographic exposure of the medial and lateral ungulae of the hindlimbs and forelimbs; abaxioaxial projections were used. The images were analyzed; distances were measured between the dorsal surface of the distal phalanx and the surface of the hoof capsule. The two angles formed, i.e., an angle between the dorsal surface of the distal phalanx and a line parallel to the sole (inner), and an angle between the dorsal surface of the hoof and a line parallel to the sole (outer), were also recorded. The results suggested a standard of normality for the proximal, middle and distal distances of the ungulae of the forelimbs: 0.96 ± 0.12 cm. For the measurement of hindlimbs, except for the distal distances of the side ungulae, the suggested value was 1.02 ± 0.14 cm; for the distal measurement of the lateral ungulae of the hindlimbs, the value was 1.09 ± 0.12 cm. For inner and outer angles, the values were 36.45° ± 4.4° for the medial ungulae of the forelimbs and 42.50° ± 3.8° for other ungulae of the forelimbs and hindlimbs (standard deviations of the values suggested for the angles should be used as variations between different animals, limbs and ungulae; they should not be used between angles of the same ungula).     

Improvement of Matrinxã, Brycon amazonicus,Larviculture by Exposing Eggs to Triiodothyronine

This work evaluated the effect of triiodothyronine (T₃) on larviculture of matrinxã, Brycon amazonicus. Oocytes of three females were pooled, fertilized with pooled semen of two males and separated in four batches that were immersed in triiodothyronine solutions as follows: M₁ (control – water); M₂ (0.01 mg/L T₃); M₃ (0.05 mg/L T₃); and M₄ (0.1 mg/L T₃). Triiodothyronine did not affect fertilization rate and number of hatched larvae. Weight of hatched larvae was significantly higher in treatments M3 and M4, as well as among larvae sampled at Day 12 in all treatments. After 12 d of rearing, biomass gain was higher in the hormone treatments (M₁ 688 ± 569 mg; M₂ 2436 ± 562 mg; M₃ 3572 ± 569 mg; and M₄ 4129 ± 770 mg). In general, coefficients of variation of weight (CV_w) and length (CV_l) did not differ among treatments and cannibalism was registered between 36 and 72 hours post‐hatching (h.p.h.) without differences among treatments. Larval survival increased in the hormone treatments (M₁ 26.5%; M₂ 37.6%; M₃ 40.6%; and M₄ 40.8%). The results indicate that the immersion of matrinxã eggs in triiodothyronine can promote beneficial effects to its larviculture and indicate promising perspectives for culture of this tropical species.     

The morphology–diet relationship and its role in the coexistence of two species of annual fishes

Annual fishes, which inhabit temporary pools with extremely limited habitat complexity and niche availability, display remarkable sexual dimorphism, rapid growth, and enormous investment into reproduction, all traits associated with high energy requirement. This study tests three hypotheses for two syntopic annual fishes (Austrolebias minuano and Cynopoecilus fulgens) found in six wetlands of southern Brazil: (i) considerable morphological differences result in low dietary overlap, (ii) sexual dimorphism in both species leads to intraspecific diet segregation, and (iii) dietary richness increases during ontogenetic development, and is narrower in C. fulgens than A. minuano due to morphological limitations imposed by reduced size. The diet of 82 A. minuano and 211 C. fulgens individuals was analyzed over two annual cycles. The morphology was characterized by 26 measurements covering the entire body of both species. There was no evidence of morphological specialization related to food competition and the diet of A. minuano and C. fulgens showed high overlap. High food availability, high predator abundance, and high connectivity of adjacent wetlands are likely the main mechanisms allowing coexistence of both species. Within species, sexual dimorphism did not result in a decrease in dietary overlap, which reinforces the idea that morphological differences between the sexes did not evolve as a mechanism to decrease food competition. Large A. minuano did not have a more diverse diet than the smaller C. fulgens; however, increase in body size allowed both species to ingest larger prey. Morphological variability in both species was mainly related to ontogenetic development and reproduction.     

Effect of high temperature on pollen morphology,plant growth and seed yield in quinoa (Chenopodium quinoa Willd.)

Quinoa (Chenopodium quinoa Willd.) has gained considerable attention worldwide during the past decade due to its nutritional and health benefits. However, its susceptibility to high temperatures has been reported as a serious obstacle to its global production. The objective of this study was to evaluate quinoa growth and pollen morphology in response to high temperatures. Pollen morphology and viability, plant growth and seed set, and several physiological parameters were measured at anthesis in two genotypes of quinoa subjected to day/night temperatures of 22/16°C as a control treatment and 40/24°C as the heat stress treatment. Our results showed that heat stress reduced the pollen viability between 30% and 70%. Although no visible morphological differences were observed on the surface of the pollen between the heat‐stressed and non‐heat‐stressed treatments, the pollen wall (intine and extine) thickness increased due to heat stress. High temperature did not affect seed yield, seed size and leaf greenness. On the other hand, high temperature improved the rate of photosynthesis. We found that quinoa has a high plasticity in response to high temperature, though pollen viability and pollen wall structure were affected by high temperatures in anthesis stage. This study is also the first report of quinoa pollen being trinucleate.     

Relationships of Maximum Length,Length at First Sexual Maturity,and Growth Performance Index in Nature with Absolute Growth Rates of Intensive Cultivation of Some Tropical Marine Fish

Growth rate is one of the main biological criteria for selecting tropical marine fishes for intensive culture. Relationships of maximum observed length (MOL), length at first sexual maturity, growth performance index (Φ′), and juvenile absolute growth rate during nursery with growth rate during grow‐out periods were studied and their equations were calculated for 30 tropical or subtropical marine fish species. All equations were positive and their correlation coefficients were significant (P < 0.01). Three nomographs were made to obtain gross estimates of probable growth rates on intensive fish culture using the above relationships. Species with MOL of 100 cm or larger, length at first sexual maturity of 35 cm or more, Φ′ of 2.90 or more, and growth during the nursery period of or above 0.3 g/d, would be expected to have growth rates of at least 2 g/d during the grow‐out period. These criteria could help to identify species with best potential for intensive cultivation as a first step before a full evaluation and selection process is carried out.     

Kinetics of energy source utilization in Boophilus microplus (Canestrini, 1887) (Acari: Ixodidae) embryonic development

The present work evaluates the kinetics of utilization of the main potential energy sources throughout the embryonic developmental stages of Boophilus microplus. The embryonic development of this arthropod is completed in 21 days. Cellularization of the blastoderm occurs on the 6th day and is rapidly followed by germ band extension and segmentation, whose first signs are visible on the 7th day. Cellularization is typically a maternal-driven process, carried out by molecular determinants deposited in the oocyte during oogenesis. On the other hand, segmentation is of zygotic nature, being the consequence of the synthesis of various components by the growing embryo. The enhancement in total B. microplus RNA was observed after cellularization, corroborating the replacement of maternal-driven processes by embryonic zygotic expression. An abrupt increase in oxygen consumption was observed from cellularization until the 8th day of development. The reduction in dry weight at the same period and the susceptibility of oxygen consumption to KCN suggest that the respiration process is activated during early embryonic development. A marked decrease in total lipid content occurred between the 5th and 7th days of development, suggesting this is the main energy source for cellularization. A major reduction in carbohydrate content occurred later, between the 7th and 9th days, and it could be assigned to the morphological segmentation of the embryo. Although the total amount of proteins remains unchanged from oviposition to hatching, a 15% reduction in vitellin (VT) content was observed before cellularization, up to the 4th day after egglaying. This observation was correlated to the synthesis of new proteins needed to support early embryo development. Additional 20% of VT was consumed thereafter, mainly at the end of embryogenesis, and in this case VT is probably used as energy source to the older embryo. Altogether, these data indicate different energy sources for maternal and zygotic driven processes.