Spawning in Labeo bata occurs during July and August. Each individual spawns only once, with the onset of spawning directly dependent on the monsson season. Its success depends upon the access of gravid fish to a suitable spawning ground. The average fecundity is 192 785. 相似文献
Root growth response of 10-days-oldseedlings of 100 maize accessions at, 0 mM, 60 mM, 80 mM and 150 mM NaCl concentration
was assessed in solution culture. The non-linear least square method was used to quantify the salt tolerance of maize accessions.
The estimated salinity threshold, Ct, the NaCl concentration at which root growth starts to decrease, C0, and C50, the concentrations
at which roots stop growing and 50% of its control value revealed considerable differences between the accessions. No general
consistency for tolerance was, however, found between the estimates of Ct and C50. Different genetic systems appeared to be
involved in controlling the inheritance of Ct and C50.Both Ct and C50 appeared to quantify accession tolerance, and the expression
of root growth as a function of NaCl concentrations provides a useful guideline for salt tolerance. Estimates of broad sense
heritability for relative root length were moderate in size (0.62 to 0.82), suggesting the scope for enhancing salt tolerance
in maize through selection and breeding.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
Soliva sessilis (Burweed) is a winter annual weed found in wheat crop of Pakistan. It is thought to have an allelopathic effect on wheat crop. In this regard, an experiment was conducted in 2019 in the department of Weed Science and Botany at the University of Agriculture Peshawar, to assess the allelopathic potential of S. sessilis on various wheat varieties grown in Peshawar, Pakistan. Physiologically matured roots and leaves of S. sessilis were dried, ground and stored. Three common wheat varieties were selected for the research including Atta Habib, Pirsabaq-15, and Shahkar-13. The treatments of the experiment comprised of the aqueous extracts of the roots and leaves of S. sessilis, hot water extracts, methanol extracts, litter, and mulches. A mass of 5?g of S. sessilis was taken for the different extracts for 24?h, however, the methanol extract was kept for 48?h. The effect of the treatments was highly significant on wheat seed germination, radicle length, plumule length, fresh biomass as well as dry biomasses of the three tested wheat varieties. The variety Atta Habib was discovered as the most susceptible variety to the treatments of aqueous extracts, hot water extracts, and leaves’ litter. In contrary, the variety Pirsabaq-15 exhibited a remarkable increase in the various data collection parameters. The leaves of S. sessilis were observed more toxic as compared to the roots. The mulch of S. sessilis indicated stimulatory effect on the wheat varieties. For the interaction effect between treatments and varieties, the leaves and roots aqueous extract and their litter showed inhibitory effect. In conclusion, the leaves and roots of S. sessilis are potentiality allelopathic to wheat crop plants and further study is needed to assess the types of these allelochemicals present in the leaves and roots of the weed.
Seedling vigor is the basic component of the transplanted rice, which depends on its growing environment and proper age. Thus the influence of nursery management and seedling age was evaluated after transplanting 10, 20, 30, and 40-days older seedlings raised by using seed rate (high and low) and nitrogen (N) (with and without) in rice growing season 2008 and 2009. Study revealed that 10-days older nursery seedlings, irrespective to nursery-bed treatments, showed accelerated growth start after transplanting in main field while at later stages significant interaction was observed. Transplanting of 20-days older fertilized seedlings grown at low seeding density at nursery-bed resulted in similar growth performance as in younger. Maximum net-benefit (45111, 44402 Rs. ha?1) was recorded with transplanting 10-days older nursery seedlings while the fertilized seedlings grown at lower seeding density recorded highest net-benefit (37908, 36780 Rs. ha?1) in both the years. 相似文献
Tropical forest biodiversity is declining, but the resulting effects on key ecosystem services, such as carbon storage and sequestration, remain unknown. We assessed the influence of the loss of tropical tree species on carbon storage by simulating 18 possible extinction scenarios within a well-studied 50-hectare tropical forest plot in Panama, which contains 227 tree species. Among extinction scenarios, aboveground carbon stocks varied by more than 600%, and biological insurance varied by more than 400%. These results indicate that future carbon storage in tropical forests will be influenced strongly by future species composition. 相似文献
