Sowing

About: Sowing is a research topic. Over the lifetime, 33888 publications have been published within this topic receiving 273438 citations. The topic is also known as: seeding.

The promotive effect of smoke derived from burnt native vegetation on seed germination of Western Australian plants

Abstract: Exposure of dormant seed to cold smoke derived from burnt native vegetation had a positive influence on germination in one or more seed provenances in 45 out of 94 species of native Western Australian plants that are normally hard to germinate. When tested under controlled conditions some species showed earlier germination in smoke treatments than controls; in others smoke-treated seeds continued to germinate for several weeks after controls had achieved full germination. In the remainder, treated and control seeds germinated to similar time schedules. A group of 23 species which responded positively had previously been recorded as extremely difficult or impossible to germinate using conventional techniques. These included members of the genera Geleznowia (Rutaceae), Hibbertia (Dilleniaceae), Stirlingia (Proteaceae), Verticordia (Myrtaceae), Actinostrobus (Cupressaceae) and Pimelea (Thymelaeaceae). Both large- and small-seeded species were encountered amongst the positively responding taxa, which encompassed representatives of 15 families and 26 genera of dicotyledons, 5 families and 8 genera of monocotyledons and the gymnosperm Actinostrobus acuminatus. Sowing seeds on smoke-fumigated filter papers or watering with aqueous eluates of smoke elicited similar degrees of stimulation of germination, as did exposure to gaseous smoke in a readily germinating species Anigozanthos manglesii (Haemodoraceae) and the normally intractable species Lysinema ciliatum (Epacridaceae). Exposing recently burnt and unburnt natural bushland sites to smoke, smoked water or smoked dry sand elicited a significant germination response in 15 species. Over one third of the species sampled in the burnt site exhibited germination additional to that caused by the fire. Data are discussed in relation to previous germination studies on Australian and other taxa.

Principles of Natural Regeneration of Tropical Dry Forests for Restoration

Abstract: Tropical dry forests are the most threatened tropical terrestrial ecosystem. However, few studies have been conducted on the natural regeneration necessary to restore these forests. We reviewed the ecology of regeneration of tropical dry forests as a tool to restore disturbed lands. Dry forests are characterized by a relatively high number of tree species with small, dry, wind-dispersed seeds. Over small scales, wind-dispersed seeds are better able to colonize degraded areas than vertebrate-dispersed plants. Small seeds and those with low water content are less susceptible to desiccation, which is a major barrier for establishment in open areas. Seeds are available in the soil in the early rainy season to maximize the time to grow. However, highly variable precipitation and frequent dry spells are important sources of mortality in seeds and seedlings. Collecting seeds at the end of the dry season and planting them when soil has sufficient moisture may increase seedling establishment and reduce the time they are exposed to seed predators. Germination and early establishment in the field are favored in shaded sites, which have milder environment and moister soil than open sites during low rainfall periods. Growth of established seedlings, however, is favored in open areas. Therefore, clipping plants around established seedlings may be a good management option to improve growth and survival. Although dry forests have species either resistant to fire or that benefit from it, frequent fires simplify community species composition. Resprouting ability is a noticeable mechanism of regeneration in dry forests and must be considered for restoration. The approach to dry-forest restoration should be tailored to this ecosystem instead of merely following approaches developed for moister forests.

Seed mass and the competition/colonization trade-off: a sowing experiment

Abstract: Summary 1 A seed-addition experiment using seven co-occurring annual plant species with a range of seed masses was carried out in a limestone grassland in South Wales. 2 If seedlings compete for establishment sites, then large seed size may confer enhanced competitive ability. However, the simple reciprocal relationship found between seed mass and per capita seed output showed that species producing larger seeds suffer reduced fecundity. Seed size may therefore act as a surrogate in a competition/colonization trade-off. 3 Equal numbers of seeds of all species were sown in a mixture over a range of densities. As sowing density increases, all species should reach a higher proportion of the available microsites. If large-seeded species are the best competitors they are expected to win all the sites they reach, and hence to occupy an increasing proportion of sites as sowing density increases. 4 The three species with the largest seeds made up 49% of individuals at low-density sown plots but 83% of individuals in high-density sown plots. In addition, seed mass and plant density were not correlated in unsown plots, but were strongly correlated in high-density sown plots. However, all small-seeded species maintained a presence in sown plots. 5 Although species were sown at random with respect to one another, individuals were up to five times more likely than expected to have a conspecific as a nearest neighbour. This could be caused by interspecific competition and/or by environmental heterogeneity that favours different species in different patches. 6 The results suggest that seedlings do compete for establishment sites and that large-seeded species generally win when in direct competition. In unsown areas small-seeded species win many sites by forfeit (because large-seeded species are strongly recruitment limited) but there may be a restricted subset of potential sites for which they are the best competitors and which they can win outright.

Knott's Handbook for Vegetable Growers

Abstract: PREFACE. PART 1: VEGETABLES AND THE VEGETABLE INDUSTRY. 01 BOTANICAL NAMES OF VEGETABLES NAMES OF VEGETABLES IN NINE LANGUAGES. 02 EDIBLE FLOWERS. 03 U.S. VEGETABLE PRODUCTION. 04 CONSUMPTION OF VEGETABLES IN THE U.S. 05 WORLD VEGETABLE PRODUCTION. 06 NUTRITIONAL COMPOSITION OF VEGETABLES. PART 2: PLANT GROWING AND GREENHOUSE VEGETABLE PRODUCTION. TRANSPLANT PRODUCTION. 01 PLANT GROWING CONTAINERS. 02 SEEDS AND SEEDING. 03 TEMPERATURE AND TIME REQUIREMENTS. 04 PLANT GROWING MIXES. 05 SOIL STERILIZATION. 06 FERTILIZING AND IRRIGATING TRANSPLANTS. 07 PLANT GROWING PROBLEMS. 08 CONDITIONING TRANSPLANTS. 09 ADDITIONAL TRANSPLANT PRODUCTION WEBSITES AND REFERENCES GREENHOUSE CROP PRODUCTION. 10 CULTURAL MANAGEMENT. 11 CARBON DIOXIDE ENRICHMENT. 12 SOILLESS CULTURE. 13 NUTRIENT SOLUTIONS. 14 TISSUE COMPOSITION. 15 ADDITIONAL SOURCES OF INFORMATION ON GREENHOUSE VEGETABLES. PART 3: FIELD PLANTING. 01 TEMPERATURES FOR VEGETABLES. 02 SCHEDULING SUCCESSIVE PLANTINGS. 03 TIME REQUIRED FOR SEEDLING EMERGENCE. 04 SEED REQUIREMENTS. 05 PLANTING RATES FOR LARGE SEEDS. 06 SPACING OF VEGETABLES. 07 PRECISION SEEDING. 08 SEED PRIMING. 09 VEGETATIVE PROPAGATION. 10 POLYETHYLENE MULCHES. 11 ROW COVERS. 12 WINDBREAKS. 13 ADDITIONAL SOURCES OF INFORMATION ON PLASTICULTURE. PART 4: SOILS AND FERTILIZERS. 01 NUTRIENT BEST MANAGEMENT PRACTICES. 02 ORGANIC MATTER. 03 SOIL-IMPROVING CROPS. 04 MANURES. 05 SOIL TEXTURE. 06 SOIL REACTION. 07 SALINITY. 08 FERTILIZERS. 09 FERTILIZER CONVERSION FACTORS. 10 NUTRIENT ABSORPTION. 11 PLANT ANALYSIS. 12 SOIL TESTS. 13 NUTRIENT DEFICIENCIES. 14 MICRONUTRIENTS. 15 FERTILIZER DISTRIBUTORS. PART 5: WATER AND IRRIGATION. 01 SUGGESTIONS ON SUPPLYING WATER TO VEGETABLES. 02 ROOTING OF VEGETABLES. 03 SOIL MOISTURE. 04 SURFACE IRRIGATION. 05 OVERHEAD IRRIGATION. 06 DRIP OR TRICKLE IRRIGATION. 07 WATER QUALITY. PART 6: VEGETABLE PESTS AND PROBLEMS. 01 AIR POLLUTION. 02 INTEGRATED PEST MANAGEMENT. 03 SOIL SOLARIZATION. 04 PESTICIDE USE PRECAUTIONS. 05 PESTICIDE APPLICATION AND EQUIPMENT. 06 VEGETABLE SEED TREATMENT. 07 NEMATODES. 08 DISEASES. 09 INSECTS. 10 PEST MANAGEMENT IN ORGANIC PRODUCTION SYSTEMS. 11 WILDLIFE CONTROL. PART 7: WEED MANAGEMENT. 01 WEED MANAGEMENT STRATEGIES. 02 WEED IDENTIFICATION. 03 NOXIOUS WEEDS. 04 WEED CONTROL IN ORGANIC FARMING. 05 COVER CROPS AND ROTATION IN WEED MANAGEMENT. 06 HERBICIDES. 07 WEED CONTROL RECOMMENDATIONS. PART 8: HARVESTING, HANDLING, AND STORAGE. 01 FOOD SAFETY. 02 GENERAL POSTHARVEST HANDLING PROCEDURES. 03 PREDICTING HARVEST DATES AND YIELDS. 04 COOLING VEGETABLES. 05 VEGETABLE STORAGE. 06 CHILLING AND ETHYLENE INJURY. 07 POSTHARVEST DISEASES. 08 VEGETABLE QUALITY. 09 U.S. STANDARDS FOR VEGETABLES. 10 MINIMALLY PROCESSED VEGETABLES. 11 CONTAINERS FOR VEGETABLES. 12 VEGETABLE MARKETING. PART 9: VEGETABLE SEEDS. 01 SEED LABELS. 02 SEED GERMINATION TESTS. 03 SEED GERMINATION STANDARDS. 04 SEED PRODUCTION. 05 SEED YIELDS. 06 SEED STORAGE. 07 VEGETABLE VARIETIES. 08 VEGETABLE SEED SOURCES. PART 10: APPENDIX. 01 SOURCES OF VEGETABLE INFORMATION. 02 PERIODICALS FOR VEGETABLE GROWERS. 03 U.S. UNITS OF MEASUREMENT. 04 CONVERSION FACTORS FOR U.S. UNITS. 05 METRIC UNITS OF MEASUREMENT. 06 CONVERSION FACTORS FOR SI AND NON SI UNITS. 07 CONVERSIONS FOR RATES OF APPLICATION. 08 WATER AND SOIL SOLUTION CONVERSION FACTORS. 09 HEAT AND ENERGY EQUIVALENTS AND DEFINITIONS. INDEX.

Changes in endogenous abscisic acid levels during dormancy release and maintenance of mature seeds: studies with the Cape Verde Islands ecotype, the dormant model of Arabidopsis thaliana

Abstract: Mature seeds of the Cape Verde Islands (Cvi) ecotype of Arabidopsis thaliana (L.) Heynh. show a very marked dormancy. Dormant (D) seeds completely fail to germinate in conditions that are favourable for germination whereas non-dormant (ND) seeds germinate easily. Cvi seed dormancy is alleviated by after-ripening, stratification, and also by nitrate or fluridone treatment. Addition of gibberellins to D seeds does not suppress dormancy efficiently, suggesting that gibberellins are not directly involved in the breaking of dormancy. Dormancy expression of Cvi seeds is strongly dependent on temperature: D seeds do not germinate at warm temperatures (20–27°C) but do so easily at a low temperature (13°C) or when a fluridone treatment is given to D seeds sown at high temperature. To investigate the role of abscisic acid (ABA) in dormancy release and maintenance, we measured the ABA content in both ND and D seeds imbibed using various dormancy-breaking conditions. It was found that dry D seeds contained higher amounts of ABA than dry ND after-ripened seeds. During early imbibition in standard conditions, there was a decrease in ABA content in both seeds, the rate of which was slower in D seeds. Three days after sowing, the ABA content in D seeds increased specifically and then remained at a high level. When imbibed with fluridone, nitrate or stratified, the ABA content of D seeds decreased and reached a level very near to that of ND seeds. In contrast, gibberellic acid (GA3) treatment caused a transient increase in ABA content. When D seeds were sown at low optimal temperature their ABA content also decreased to the level observed in ND seeds. The present study indicates that Cvi D and ND seeds can be easily distinguished by their ability to synthesize ABA following imbibition. Treatments used here to break dormancy reduced the ABA level in imbibed D seeds to the level observed in ND seeds, with the exception of GA3 treatment, which was active in promoting germination only when ABA synthesis was inhibited.