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Pre-emergence herbicides affect seedling emergence of tropical forest tree species

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Journal of Forestry Research 2017年第4期28卷 733-739页

作者： Diego Cerveira de Souza Vera Lex Engel Forest Science Department Agronomic Sciences College-FCASao Paulo State University – UNESPP.O. Box 237BotucatuSP 18603-970Brazil

Testing techniques to reduce weed infestation is a crucial step in developing direct tree seeding systems. The use of pre-emergence herbicides may be an alternative to manual weeding techniques, but so far, information on how they affect the seeds of native tree species is scarce. We established a greenhouse experiment to evaluate the effects of four pre-emergence herbicides (atrazine, diuron, isoxaflutole and oxyfluorfen) on weed suppression and seedling emergence and early growth of seven tropical forest tree species (Annona coriacea Mart., Citharexylum myrianthum Cham., Cordia ecalyculata Vell., Peltophorum dubium (Spreng.) Taub., Psidium guajava L., Pterogyne nitens Tul. and Schinus terebinthifolia Raddi). The experimental design was a randomized complete block design with five treatments and five replicates. The treatments consisted of a single dose of each pre-emergence herbicide and a control. Throughout the 60 days after sowing we evaluated weed cover and seedling emergence and early growth of tree species. Overall, our results suggest that all tested herbicides reduced weed cover; however, they also negatively affected tree species seedling emergence. Of the four herbicides tested, atrazine and diuron showed the greatest effects on tree seedling emergence, oxyfluorfen was least aggressive towards native species and isoxaflutole was most effective in weed control. Native tree species varied in their responses to herbicides, indicating that future experiments should increase the number of species tested as well as investigate how seed traits can affect the species responses to different herbicides.

关键词： Pre-emergence herbicides Weed control Direct seeding seedling emergence Tropical seasonal forests

Changes in Nutrient-Homeostasis and Reserves Metabolism During Rice Seed Priming:Consequences for seedling emergence and Growth

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Agricultural Sciences in China 2010年第2期9卷 191-198页

作者： Muhammad Farooq Shahzad M A Basra Abdul Wahid Nazir Ahmad Department of Agronomy University of AgricultureFaisalabad Department of Crop Physiology University of AgricultureFaisalabad Department of Botany University of AgricultureFaisalabad

In this study influence of different seed priming treatments on the nutrient-homeostasis and reserve metabolism during seedling emergence and growth of rice were determined. Seed priming treatments included pre-germination, hydropriming for 48 h, osmohardening with KCl and CaCl2, ascorbate priming and hardening. All treatments shortened the emergence time and enhanced the energy and index of seedling emergence. seedlings from primed seeds had greater length, number of roots and fresh and dry mass than control. Among the treatments, CaCl2, ascorbate and KCl proved better in enhancing emergence and seedling growth. Seed priming changed the pattern of N and Ca^2＋ homeostasis both of the seeds and seedlings, which were associated to enhancing s-amylase activity and reducing sugars content. Positive correlations of seedling attributes with nutrient content suggested that as a result of seed priming, most of N and Ca^2＋ were partitioned to embryo, which enhanced seedling emergence and subsequent growth of rice seedlings.

关键词： rice α-amylase activity nutrient homeostasis seedling emergence seedling vigor

Responses of Caryopsis Germination, seedling emergence, and Development to Sand Water Content of Agropyron cristatum （L.） Gaertn. and Bromus inermis Leyss.

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Journal of Integrative Plant Biology 2005年第12期47卷 1450-1458页

作者： Hui-Ling YANG Xuan-Wei ZHU Ming DONG Zhen-Ying HUANG Zhi-Ping CAO College of Resources and Environmental Sciences China Agricultural University Beijing 100094 China Laboratory of Quantitative Vegetation Ecology Institute of Botany the Chinese Academy of Sciences Beijing 100093 China

Responses of caryopsis germination, seedling emergence, and development of Agropyron cristatum （L.） Gaertn. （Gramineae） and Bromus inermis Leyss. （Gramineae）, two dominant perennial grasses in the Otindag Sandland of China, to different sand water content （SWC; 1%, 2%, 3%, 4%, 6%, 8%, 12%, 16%, and 20%） were studied comparatively. The results showed that the germination responses of the two grasses to SWC were similar （i.e. caryopses could not germinate when the SWC was below 3%; at SWC ranging from 3% to 12%, the higher the SWC, the higher the germination percentage; and at a SWC of 12%-20%, germination reached similarly high percentages）. At a sand burial depth of 0.5 cm, the threshold of SWC for seedling emergence was 6% forA. cristatum and 8% forB. inermis; at 12%-20% SWC, the seedling emergence of both species reached similarly high percentages. The seedling growth responses of these two species to SWC gradients were different. For A. cristatum, the biomass of seedlings increased with SWC from 6% to 12%, and decreased with SWC from 12% to 20%. For B. inermis, the biomass of seedlings always increased with SWC from 8% to 20%. The results also showed that the seedlings of both species allocated more biomass to the roots with decreases in SWC. The SWC changes from April to October in natural microhabitats of both species suggested that the SWC may play an important role in caryopsis germination, seedling emergence, and the growth characteristics of the two grasses. The responses of caryopsis germination, seedling emergence, and the growth characteristics of these two species to SWC may determine their distribution pattems in the Otindag Sandland.

关键词： Agropyron cristatum Bromus inermis caryopsis germination Otindag Sandland sand water content seedling emergence seedling growth characteristics.

Precipitation amount and frequency affect seedling emergence and growth of Reaumuria soongarica in northwestern China

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Journal of Arid Land 2018年第4期10卷 574-587页

作者： SHAN Lishan ZHAO Wenzhi LI Yi ZHANG Zhengzhong XIE Tingting Northwest Institute of Eco-Environment and Resources Chinese Academy of Sciences College of Forestry Gansu Agricultural University

Climate change is shifting the amount and frequency of precipitation in many regions, which is expected to affect seedling recruitment across ecosystems. However, the combined effects of precipitation amount and frequency on seedling recruitment remain largely unknown. An understanding of the effects of precipitation amount and frequency and their interaction on seedling emergence and growth of typical desert plants is vital for managing populations of desert plants. We conducted two experiments to study the effects of variation in precipitation on Reaumuria soongarica （Pall.） Maxim. First, greenhouse experiments were conducted to examine the effects of three precipitation amount treatments （ambient, ＋30%, and -30%） and two precipitation frequency treatments （ambient and -50%） on seedling emergence. Second, the morphological responses of R. soongarica to changes in precipitation amount and frequency were tested in a controlled field experiment. Stage-specific changes in growth were monitored by sampling in different growth seasons. Our results showed that precipitation amount significantly affected germination, seedling emergence, and growth of R. soongarica, and there was a larger effect with decreased precipitation frequency compared with ambient. Germination and seedling emergence increased as precipitation increased under the same frequency of precipitation. The highest emergence percentage was obtained with a 30% increase in precipitation amount and a 50% reduction in precipitation frequency. Compared with ambient precipitation, a 30% increase in precipitation amount increased above- and below-ground biomass accumulation of R. soongarica during the growth season. A decrease of 30% in precipitation amount also resulted in an increase in below-ground biomass and root/shoot ratio in the early stages of the growth season, however, above- and below-ground biomass showed the opposite results at the end of the growth season, with larger effects on above-ground than be

关键词： precipitation patterns seedling emergence biomass root/shoot ratio seedling recruitment

Study on Seed Bank Composition and seedling emergence Regularity in Placer Iron Ore Soil

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Journal of Resources and Ecology 2022年第2期13卷 312-318页

作者： HOU Yurong KE Mei WEI Peng LAN Jiyong LI Chao KANG Shuai KAYRAT Aldeyarhan WANG Lu Institute of Grassland Science Xinjiang Academy of Animal HusbandryUrumqi 830000China Altay Prefecture Bureau of Ecology and Environment(Environmental Monitoring Station) Xinjiang 836500China

The mining of placer iron ore greatly influences the surrounding desert *** Agdala Town,Qinghe County,Xinjiang,the soil seed bank is severely damaged,and the utilization and productivity of desert grasslands are almost zero,which seriously affects the safety of the ecological environment and the development of local animal *** is very important to supplement soil seed banks to enhance the species composition of desert grasslands after ecological *** this study,the effects of the seed bank,species composition,and seed burial depth on the seedling emergence rate at placer iron ore site before and after artificial seed bank replenishment were compared using the germination tray *** original soil seed bank in the study area contained only four species,which were all annual *** dominant species were Salsola ruthenica and Corispermum orientale,and the soil seed bank density was very *** emergence regularity of the soil seed bank was closely related to water content,and the emergence of annual vegetation was *** burial depth affected the emergence rate of perennial grass,and we determined that a burial depth of 0–5 cm was the most effective for *** indicates that seedling emergence of artificially supplemented soil seed bank can be completed within 7 days if the sowing depth is appropriate;sowing depths greater than 5 cm affect seed *** findings provide a basis for selecting species to populate large areas.

关键词： seedling emergence placer iron ore soil seed band species composition

Field Experiment for the Effects of Rice Straw Returning and Seeding Pattern on Wheat seedling emergence and Grain Yield

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Agricultural Science & Technology 2017年第12期18卷 2357-2361,2382页

作者：张斯梅顾克军樊平声许博张传辉顾东祥张恒敢于建光杨四军江苏省农业科学院农业资源与环境研究所江苏南京210014

In order to study the effect of rice straw returning and seeding patterns on seedling emergence and grain yield, field experiment was conducted to investi- gate the effects of straw mechanized returning and different seeding patterns on e- mergence rate, emergence uniformity and yield traits of wheat after rice. The results were as follows： in rice straw removal treatments, the emergence rate of mechani- cal seeding in drill was lower than that of mechanical uniform planting and manual broadcast sowing, which were 51.84%, 90.89% and 88.87%, respectively; the emer- gence uniformity of manual broadcast sowing was inferior to mechanical seeding in drill and mechanical uniform planting, which were 0.49, 0.26 and 0.23, respectively. As for the treatments with rice straw returning to the field, the emergence rate and emergence uniformity all decreased in the three seeding patterns, of which mechan- ical seeding in drill dropped markedly with emergence rate decreased by 36.54%. The emergence rate and emergence uniformity affected grain yield by affecting pan- icle, grains per spike and 1 000-grain weight. The grain yield for the treatment with rice straw removal was 6 091.34 kg/hm2, while that with rice straw returning to field was 6 476.20 kg/hm2, and both were higher than the yields of the other two seed- ing patterns. Therefore, mechanical uniform planting was？recommended for its higher emergence rate, better emergence uniformity, which was conductive to increase grain yield in wheat after rice production with rice straw returning to field.

关键词： Straw returning Seeding pattern Wheat after rice seedling emergence Yield

Potentiality of Different Seed Priming Agents to Mitigate Cold Stress of Winter Rice seedling

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Phyton-International Journal of Experimental Botany 2021年第5期90卷 1491-1506页

作者： Md.Parvez Anwar Md.Ariful Islam Khalid A.K.M.Mominul Islam Sabina Yeasmin Sharif Ahmed Adel Hadifa Ismail A.Ismail Akbar Hossain Ayman EL Sabagh Agro Innovation Laboratory Department of AgronomyBangladesh Agricultural UniversityMymensingh2202Bangladesh International Rice Research Institute Bangladesh OfficeDhaka1213Bangladesh Rice Research and Training Center Field Crops Research InstituteAgricultural Research CenterSakha33717Egypt Department of Biology College of ScienceTaif UniversityTaif21944Saudi Arabia Bangladesh Wheat and Maize Research Institute Dinajpur5200Bangladesh Department of Agronomy Faculty of AgricultureKafrelsheikh UniversityKafr Elsheikh33516Egypt

Seed priming has proved to be an effective pre-germination seed invigoration technique for different crops to improve seed and seedling performance under different abiotic *** Bangladesh,winter rice is very often exposed to cold waves just after sowing in the nursery bed resulting in poor seed germination and seedling emergence,yellowish and thin seedlings production,and a very low survival *** priming may mitigate the cold stress during seed germination and seedling emergence and helps in the quality seedling production of winter *** evaluate the efficacy of different seed priming techniques in increasing seedling emergence,growth,vigor and survivability of winter rice cultivars under cold stress,a pot experiment was conducted at the Department of Agronomy,Bangladesh Agricultural University during December 2018 to January *** experiment comprised two factors,(A)Winter rice variety namely,(i)BRRI dhan29 and (ii)BRRI dhan36;(B)Seed priming agent namely (i)Control(no priming),(ii)20000 ppm NaCl,(iii)30000 ppm NaCl,(iv)20000 ppm KCl,(v)30000 ppm KCl,(vi)20000 ppm CaCl2,(vii)30000 ppm CaCl2,(viii)50 ppm CuSO4,(ix)75 ppm CuSO_(4),(x)10000 ppm ZnSO4,(xi)15000 ppm ZnSO4,(xii)2 ppm Na2MoO4,(xiii)3 ppm Na2MoO4,(xiv)100 ppm PEG(Polyethylene glycol 4000)and (xv)150 ppm *** were sown on two different dates viz.,1st December and 1st January so that seedlings are exposed to cold stress at different *** experiment was laid out in a completely randomized design(CRD)with three *** indicated that(in most of the cases)seed priming has a positive impact on seedling emergence rate(%),root length,shoot length,root shoot ratio,root dry weight,shoot dry weight,seedling dry weight and survival rate(%).Among the priming agents,KCl and CaCl2 performed best;while priming with NaCl and PEG showed no advantages over no priming for both the sowing *** general,BRRI dhan36 performed better than BRRI dhan29 in terms of seedling growth because

关键词： Seed invigoration seedling emergence seedling mortality seedling growth low temperature stress

Ecological role of physical dormancy in seeds of Oxytropis racemosa in a semiarid sandland with unpredictable rainfall

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Journal of Plant Ecology 2018年第4期11卷 542-552页

作者： Dandan Hu Jerry M.Baskin Carol C.Baskin Xuejun Yang Zhenying Huang State Key Laboratory of Vegetation and Environmental Change Institute of BotanyChinese Academy of SciencesNo.20 NanxincunXiangshanHaidian DistrictBeijing 100093P.R.China University of Chinese Academy of Sciences No.19(A)Yuquan RoadShijingshan DistrictBeijing 100039P.R.China Department of Biology University of KentuckyLexingtonKY 40506USA Department of Plant and Soil Sciences University of KentuckyLexingtonKY 40546USA

Aims Seed dormancy and the soil seed bank are crucial to plant regeneration strategy,especially in semiarid ecosystems with unpredictable *** aim of this study was to investigate how seed dormancy is controlled by environmental factors and how it is correlated with the soil seed bank and regeneration of the perennial legume Oxytropis race-mosa,a dominant perennial herb in Mu Us Sandland of semiarid *** Germination and imbibition experiments on fresh intact and scarified seeds of *** were used to identify physical dormancy(PY)in seeds of this *** seed bank dynamics,timing of seedling emer-gence and the fate of buried seeds in the natural habitat were *** Findings PY was broken by mechanical scarification or wet heat/ice water cycles but not solely by dry heat or wet heat *** soil seed bank exhibited seasonal changes in the number of seeds,which was highest in September and lowest in *** buried at different sand depths gradually lost dormancy;20-42%of the seeds remained dormant after 20 months of *** break occurs grad-ually throughout the *** results indicate that *** exhibits hardcoatedness heterogeneity that spreads germination of a seed cohort between seasons and years in the semiarid environ-ment,where the amount of precipitation during the growing season is highly variable.

关键词： Oxytropis racemosa physical dormancy seedling emergence soil moisture soil seed bank soil temperature unpredictable rainfall

Earthworms promote greater richness and abundance in the emergence of plant species across a grassland-forest ecotone

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Journal of Plant Ecology 2016年第6期9卷 703-711页

作者： Julia Clause Sébastien Barot Estelle Forey Ecodiv URA/EA-1293 Normandie UniversitéUniversitéde RouenIRSTEASFR Scale 4116UFR Sciences et Techniques76821 Mont Saint Aignan CedexFrance Centre de Formation sur l'Environnement et la Société(CERES) Ecole Normale Supérieure24 Rue Lhomond75231 Paris Cedex 5France IRD-iEES Paris 7quai St Bernard75230 Paris Cedex 05France

Aims Chalk grasslands are subject to vegetation dynamics that range from species-rich open grasslands to tall and encroached grasslands,and woods and *** grasslands,earthworms impact plant communities and ecosystem functioning through the modification of soil physical,chemical and microbiological properties,but also through their selective ingestion and vertical transportation of seeds from the soil seed *** experiments showed that seed-earthworm interactions are species specific,but little is known on the impact of seed-earthworm interactions in the *** overall aim of this study was to better understand seed-earthworm interactions and their impact on the plant *** we analyzed the composition of seedlings emerging from casts after earthworm *** we compared seedling composition in casts to the plant composition of emerging seedlings from the soil and of the aboveground vegetation along four stages of the secondary succession of chalk *** Four stages of the secondary succession of a chalk grassland—from open sward to woods—were sampled in Upper Normandy,France,in February *** each successional stage(×3 replicates),we sampled the standing vegetation,soil seed bank at three soil depths(0-2,2-5 and 5-10 cm)and earthworm surface casts along *** and cast samples were water sieved before samples were spread onto trays and placed into a *** seedlings were counted and *** of successional stage and origin of samples on mean and variability of abundance and species richness of seedlings emerging from casts and soil seed banks were *** compositions were compared between all sample *** used generalized mixed-effect models and a distance-based redundancy multivariate *** Findings seedling abundance was always higher in earthworm casts than in the soil seed bank and increased up to 5-fold,4-fold and 3.5-fold,respectively,in the tall grasslan

关键词： aboveground-belowground interactions earthworm casts seedling emergence secondary succession seed bank