scholarly journals Germination response of invasive plants to soil burial depth and litter accumulation is species‐specific

2020 ◽  
Vol 31 (6) ◽  
pp. 1079-1087 ◽  
Author(s):  
Judit Sonkoly ◽  
Orsolya Valkó ◽  
Nóra Balogh ◽  
Laura Godó ◽  
András Kelemen ◽  
...  
Author(s):  
Judit Sonkoly ◽  
Orsolya Valkó ◽  
Nóra Balogh ◽  
Laura Godó ◽  
András Kelemen ◽  
...  

AbstractQuestionsPlant invasions are considered among the biggest threats to biodiversity worldwide. In a full-factorial greenhouse experiment we analysed the effect of soil burial depth and litter cover on the germination of invasive plants. We hypothesised that (i) burial depth and litter cover affect the germination of the studied species, (ii) the effects of burial and litter cover interact with each other, and (iii) the effects are species-specific, but dependent on seed size.MethodsWe tested the germination and seedling growth of 11 herbaceous invasive species in a full-factorial experiment using four levels of seed burial depths and litter cover. We analysed the effect of burial, litter cover, and their interactions on germination, seedling length and biomass across species and at the species level.ResultsSoil burial depth and litter cover had a significant effect on the germination of the studied species, but there were considerable differences between species. We observed a general trend of species with bigger seeds being not or less seriously affected by soil burial and litter cover than smaller-seeded species. Correlations between seed weight and effect sizes mostly confirmed this general trend, but not in the case of soil burial.ConclusionsOur findings confirmed that seed size is a major driver of species’ response to litter cover and to the combined effects of litter cover and soil burial, but there is no general trend regarding the response to soil burial depth. Despite its very small seeds the germination of Cynodon dactylon was not affected by soil burial. The germination of Ambrosia artemisiifolia was hampered by both soil burial and litter cover despite its relatively large seeds. Thus, specific information on species’ response to burial depth and litter accumulation is crucial when planning management or restoration in areas threatened by plant invasions.


Weed Science ◽  
2011 ◽  
Vol 59 (2) ◽  
pp. 182-187 ◽  
Author(s):  
Grace E-K. Bolfrey-Arku ◽  
Bhagirath S. Chauhan ◽  
David E. Johnson

Itchgrass is a weed of many crops throughout the tropics and one of the most important grass weeds of rainfed rice. Experiments were conducted in the laboratory and screenhouse to determine the effects of light, alternating day/night temperatures, high temperature pretreatment, water stress, seed burial depth, and rice residue on seed germination and seedling emergence of itchgrass in the Philippines. Two populations were evaluated and the results were consistent for both populations. Germination in the light/dark regime was greater at alternating day/night temperatures of 25/15 C than at 35/25, 30/20, or 20/10 C. Light was not a requirement for germination, but a light/dark regime increased germination by 96%, across temperature and population. A 5-min high temperature pretreatment for 50% inhibition of maximum itchgrass germination ranged from 145 to 151 C with no germination when seeds were exposed to ≥ 180 C. The osmotic potential required for 50% inhibition of maximum germination was −0.6 MPa for itchgrass, although some seeds germinated at −0.8 MPa. Seedling emergence was greatest for seeds placed on the soil surface, and emergence declined with increasing soil burial depth; no seedlings emerged from seeds buried at 10 cm. The addition of rice residue to soil surface in pots at rates equivalent to 4 to 6 Mg ha−1reduced itchgrass seedling emergence. Since seedling emergence was greatest at shallow depths and germination was stimulated by light, itchgrass may become a problem in systems where soil is cultivated at shallow depths. Knowledge gained in this study could contribute to developing components of integrated weed management strategies for itchgrass.


Weed Science ◽  
2019 ◽  
Vol 67 (2) ◽  
pp. 261-266 ◽  
Author(s):  
Iraj Nosratti ◽  
Sajad Almaleki ◽  
Bhagirath S. Chauhan

AbstractSoldier thistle [Picnomon acarna(L.) Cass.] is widely distributed throughout rainfed fields across western Iran, where it decreases crop yields and interferes with harvest operations. This study was conducted to determine the influence of different factors on seed germination and seedling emergence ofP. acarna. Freshly harvested seeds were dormant and required an after-ripening period for breaking dormancy. Seed germination was greatly promoted by light. Germination occurred over a wide spectrum of constant and fluctuating temperature regimes, ranging from 5 to 35 C, with highest germination at constant (74%) and fluctuating (94%) temperatures of 20 and 20/10 C. Seed germination ofP. acarnawas tolerant to osmotic potential, while salt stress significantly inhibited its germination percentage. pH was not an inhibiting factor for germination ofP. acarnaseeds. Seedling emergence decreased exponentially with an increase in seed burial depth in the soil; at soil burial depths of 4 cm or greater, no seedlings were able to reach the soil surface. The results suggest that significant seed germination ofP. acarnain rainfed fields is possible, and the weed has great potential to spread throughout rainfed systems in western Iran. Based on these results, effective control ofP. acarnacan be achieved by applying interrow cultivation in row crops and deep tillage at seedbed preparation.


2017 ◽  
Vol 10 (01) ◽  
pp. 90-98
Author(s):  
Niels A. Jorgensen ◽  
Mike J. Moechnig ◽  
Mary B. Halstvedt ◽  
Mark J. Renz

Interest exists in planting mixed forb–grass prairies in the midwestern United States. Aminopyralid or clopyralid can be used to suppress competition from invasive plants prior to seeding prairies. As these active ingredients are known to persist, concern exists that reductions in forb establishment could occur. We tested whether common midwestern forb species could tolerate an application of aminopyralid or clopyralid alone or in combination the summer prior to seeding, and whether fall dormant or spring seeding date influenced establishment. This experiment was performed in Beresford, SD, and Arlington, WI, where aminopyralid (54 or 123 g ae ha−1), clopyralid (237 and 420 g ae ha−1), or aminopyralid+clopyralid (54+237 g ae ha−1) were applied to a prepared seedbed in July of 2009. Ten forbs were seeded in November 2009 as a dormant seeding and in April 2010 as a spring seeding at both locations, and establishment was assessed 12 and 24 mo after treatment (MAT). Results were site and species specific. Time of seeding was an important driver of plant counts at both locations 12 and 24 MAT. In Wisconsin at 12 MAT, 60% of species studied exhibited higher counts in the spring seeding. This trend persisted in some, but was not consistent across all 10 species. In South Dakota, 80% of species studied had higher counts at 12 and 24 MAT, but differences were species specific and often differed from those studied in Wisconsin. Those species that had higher counts in spring seeding at 12 MAT, maintained higher counts at 24 MAT. Forbs planted in plots treated with herbicides did not differ from plots left untreated at either location. Results suggest native forbs typically seeded in the upper Midwest can tolerate these herbicides when applied at least 4 mo prior to seeding.


Weed Science ◽  
2022 ◽  
pp. 1-22
Author(s):  
Liberty B. Galvin ◽  
Deniz Inci ◽  
Mohsen Mesgaran ◽  
Whitney Brim-DeForest ◽  
Kassim Al-Khatib

Abstract Weedy rice (Oryza sativa f. spontanea Roshev.) has recently become a significant botanical pest in California rice (Oryza sativa L.) production systems. The conspecificity of this pest with cultivated rice, Oryza sativa (L.), negates the use of selective herbicides, rendering the development of non-chemical methods a necessary component of creating management strategies for this weed. Experiments were conducted to determine the emergence and early growth responses of O. sativa spontanea to flooding soil and burial conditions. Treatment combinations of four flooding depths (0, 5, 10, and 15 cm) and four burial depths (1.3, 2.5, 5, and 10 cm) were applied to test the emergence of five O. sativa spontanea accessions as well as ‘M-206’, a commonly used rice cultivar in California, for comparison. Results revealed that burial depth had a significant effect on seedling emergence. There was a 43-91% decrease in emergence between seedlings buried at 1.3 and 2.5 cm depending on the flooding depth and accession, and an absence of emergence from seedlings buried at or below 5 cm. Flooding depth did not affect emergence, but there was a significant interaction between burial and flooding treatments. There was no significant difference between total O. sativa spontanea emergence from the soil and water surfaces regardless of burial or flooding depths, implying that once the various accessions have emerged from the soil they will also emerge from the floodwater. Most accessions had similar total emergence compared to M-206 cultivated rice, but produced more dry weight than M-206 when planted at 1.3 cm in the soil. The results of this experiment can be used to inform stakeholders of the flooding conditions necessary as well as soil burial depths that will promote or inhibit the emergence of California O. sativa spontanea accessions from the weed seedbank.


2000 ◽  
Vol 78 (9) ◽  
pp. 1187-1198 ◽  
Author(s):  
Anle Tieu ◽  
Louise M Egerton-Warburton

We examined the effect of prolonged (up to 450 days) soil burial in the field on seed morphological traits (seed coat structure, permeability) to identify their potential roles in seed dormancy and release. Such traits were examined in species with seeds that demonstrated an obligate requirement for soil storage before germination: the dormant seeds of Anigozanthos manglesii D. Don, Conostylis neocymosa Hopper, Stylidium affine Sonder, and Stylidium crossocephalum F. Muell., and the deeply dormant fruits of Leucopogon conostephioides D.C. We detected species-specific and environmentally induced variation in seed morphology following soil burial. In A. manglesii and L. conostephioides, a significant deterioration of the seed coat or fruit wall and an increased permeability of the seed coat to water and solutes were correlated with germination responses. In these species, the seed coat and (or) fruit wall delayed germination until (morpho) physiological dormancy was broken. In C. neocymosa, S. affine, and S. crossocephalum, weathering of the seed coat, permeability, and germination were not correlated traits. These species appeared to possess physiological dormancy mechanisms and required environmental cues for dormancy release.Key words: physiological dormancy, soil burial, seed coat, morphology.


2021 ◽  
Author(s):  
Isaac Ray Towers ◽  
David J Merritt ◽  
Todd E Erikson ◽  
Margaret M Mayfield ◽  
John M Dwyer

Abstract Environmentally-cued germination may play an important role in promoting coexistence in Mediterranean annual plant systems if it causes niche differentiation across heterogenous microsite conditions. In this study, we tested how microsite conditions experienced by seeds in the field and light conditions in the laboratory influenced germination in twelve common annual plant species occurring in the understorey of the York gum-jam woodlands in southwest Western Australia. Specifically, we hypothesized that if germination promotes spatial niche differentiation then we should observe species-specific germination responses to light. In addition, we hypothesized that species’ laboratory germination response may depend on the microsite conditions experienced by seeds while buried. We tested the laboratory germination response of seeds of species under diurnally fluctuating light and complete darkness which were retrieved from microsites spanning local-scale environmental gradients known to influence community structure in this system. We found that seeds of six out of the twelve focal species exhibited significant positive germination responses to light but that the magnitude of these responses varied greatly. In addition, maximum germinability increased significantly across a gradient of canopy cover for two species, but we found little evidence to suggest that species’ relative light requirement for germination varied depending on microsite conditions. Our results suggest that variability in light availability may promote coexistence in this system and that the microsite conditions seeds experience in the intra-growing season period can further nuance species germination behaviour.


Oecologia ◽  
2022 ◽  
Author(s):  
Isaac R. Towers ◽  
David J. Merritt ◽  
Todd E. Erickson ◽  
Margaret M. Mayfield ◽  
John M. Dwyer

AbstractEnvironmentally cued germination may play an important role in promoting coexistence in Mediterranean annual plant systems if it causes niche differentiation across heterogeneous microsite conditions. In this study, we tested how microsite conditions experienced by seeds in the field and light conditions in the laboratory influenced germination in 12 common annual plant species occurring in the understorey of the York gum-jam woodlands in southwest Western Australia. Specifically, we hypothesized that if germination promotes spatial niche differentiation, then we should observe species-specific germination responses to light. In addition, we hypothesized that species’ laboratory germination response may depend on the microsite conditions experienced by seeds while buried. We tested the laboratory germination response of seeds under diurnally fluctuating light and complete darkness, which were collected from microsites spanning local-scale environmental gradients known to influence community structure in this system. We found that seeds of 6 out of the 12 focal species exhibited significant positive germination responses to light, but that the magnitude of these responses varied greatly with the relative light requirement for germination ranging from 0.51 to 0.86 for these species. In addition, germination increased significantly across a gradient of canopy cover for two species, but we found little evidence to suggest that species’ relative light requirement for germination varied depending on seed bank microsite conditions. Our results suggest that variability in light availability may promote coexistence in this system and that the microsite conditions seeds experience in the intra-growing season period can further nuance species germination behaviour.


2016 ◽  
pp. rtw030 ◽  
Author(s):  
Amanda R. Liczner ◽  
Diego A. Sotomayor ◽  
Alessandro Filazzola ◽  
Christopher J. Lortie

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