Effects Of Scarification Research Articles

Germination and Seedling Emergence of Three Semiarid Western North American Legumes

Few seed sources of North American forbs are available for revegetation/restoration of degraded western rangelands adapted to annual precipitation zones less than 300 mm, and those that are available are mainly wildland collected. The amount of time and resources necessary to make wildland collections in quantity results in high seed prices and variable seed quality, such that forbs have been under-represented in rangeland seeding mixes. We have previously identified western prairie clover (Dalea ornata Douglas ex Hook.), Searls’ prairie clover (Dalea searlsiae A. Gray), and basalt milkvetch (Astragalus filipes Torr. ex A. Gray) as native species adapted to low precipitation zones in the western United States for which field-grown seed production would potentially reduce seed costs and increase availability. A series of glasshouse experiments were conducted to determine the effects of scarification, planting depth, and soil composition on germination and seedling emergence of these species. All three species produce hard seeds, and scarification was necessary to increase germination and seedling emergence. Compared with a 6-mm planting depth, a planting depth of 19 mm retarded the rate of emergence for all species but only reduced the total seedling emergence for basalt milkvetch. With seed scarification in sandy soils, prairie clover seedling emergence exceeded 80% while basalt milkvetch was less than 10%. With seed scarification in soils with higher clay content, prairie clover total seedling emergence reduced to 58–70% while basalt milkvetch increased to approximately 30%. Along with enhancing stand establishment in seed production fields, these data will assist land managers in planning for optimal establishment of these species in rangeland revegetation/restoration projects.

Western lowland gorilla seed dispersal: Are seeds adapted to long gut retention times?

The degree of seed scarification in the frugivore gut, partly dependent on gut retention time, is a key component in determining the extent to which gut passage alters germination performances. Another potential benefit of gut passage arises as a result of the removal of fruit pulp which otherwise may act as a germination inhibitor. Using experiments designed to disentangle the respective effects of pulp removal (germination deinhibition) and seed scarification, and gut retention time as an explanatory variable, we investigated the effect of gut passage on germination performances (percentage and latency) of five tropical tree species dispersed by the western lowland gorilla (Gorilla g. gorilla). The percentage of seeds germinating after gut passage increased for three species, respectively, through the effects of scarification only, deinhibition only, and scarification and deinhibition combined. A negative scarification effect was observed for one species, and no effect of gut passage for another. Passage through the gut led to a decrease in germination latency of three species, as a result of the depulping of seeds. However, seed scarification resulted in germination delays for another species. The gut retention time of the five species averaged 39–56 h and had no effect on intra-specific germination performances except for one species whose germination probability increased as gut retention time increased. As gut retention time often correlates with dispersal distance, the fact that gut retention time per se does not reduce seed viability of these tropical tree species may have positive implications for their population dynamics and maintenance of genetic diversity. If no detrimental effect of gut retention time on germination performance is a general trait among tropical species, the extirpation of large frugivores with long gut retention time, such as the western lowland gorilla, would likely have negative long-term implications for tropical forests.

Environmental control of seed dormancy and germination of Mimosa calodendron (Fabaceae): implications for ecological restoration of a highly threatened environment

Rupestrian grasslands over ironstone outcrop, locally named canga, are montane ecosystems with restricted distribution known to harbor an unusually a large number of endemic plant species. These communities are highly threatened due to their high sensitivity to habitat conversions and extreme low resilience derived from anthropogenic pressure. Ecological restoration attempts on degraded rupestrian grassland areas have not yet been successful. Mimosa calodendron is an endemic canga shrub thought to play a facilitator role and, therefore, may enhance seedling recruitment in degraded areas. Since dormancy and slow germination are key factors of the biology of seeds and may hamper their use in ecological restoration, this study aimed to investigate the environmental control of seed dormancy and germination of M. calodendron seeds. We tested the effect of mechanical scarification, light and different incubation temperatures on seed germination. The effect of scarification on water uptake by seeds was also measured. M. calodendron seeds have physical dormancy and scarification was an effective treatment to promote high and rapid germination. Heat treatment also increased germination percentage of non-scarified seeds, but was less efficient than scarification. Once water uptake occurred, germination took place under a broad thermal gradient, regardless of light condition. Therefore, the germination profile of M. calodendron seems to be suitable for uncomplicated use in restoration projects, requiring only a pretreatment for dormancy release.

Efeito da escarificação de um latossolo vermelho em pós colheita de cana-de-açúcar

The cultivation of ratoon has been adopted as an essential practice to increase the longevity of ratoon cane sugar, since this practice is adopted as a feature to reduce soil compaction. With the objective of evaluating the effects of scarification on post- harvest sugar cane in soil physical properties and yield of cane sugar, an assay was performed in the region of Ponta Pora - MS, using the third ratoon. T1: variety ‘SP81 3250’ the treatments were chisel tillage depth of 15 cm + fertilizer; T2: chiseling 30 cm depth + fertilization; T3: T4 and fertilization: control without chiseling and without fertilization. The soil measurements performed were the resistance to penetration, density and porosity of the soil, and in addition plant height, diameter and number of stems; productivity and technological characteristics of cane sugar were evaluated. The chiseling caused significant differences in penetration resistance, bulk density and macroporosity in the 0-15 cm layer, but no difference were found in the 15-30 cm layer. There were no significant differences in the production of cane sugar and the technological characteristics of the crop.

Effects of Scarification and Stratification on Germination of Common Buckthorn (Rhamnus cathartica L.) seeds

Effects of Scarification and Stratification on Germination of Common Buckthorn (Rhamnus cathartica L.) seeds Rhamnus cathartica is an invasive shrub from Eurasia. A limited number of investigations have reported on the species’ germination requirements. This study looked at the effects of acid scarification and stratification at different moisture levels on germination. Both scarification and stratification hastened germination and shortened the germination period, but germination rates were significantly reduced with scarification. Moist and wet stratification without scarification yielded the highest germination rates. Results suggest R. cathartica seeds may possess two levels of dormancy. Aside from needed removal from the fruit, the seed coat also appears to promote some level of dormancy given the decreased time to germination after both scarification and stratification.

Effect of scarification on soil change and establishment of and artificial forest regeneration under Nothofagus spp. in Southern Chile

Soil scarification has been used as a silvicultura method to facilitate the regeneration of some forests, but it may have a negative impact on the properties of the soil. We evaluated the effect of a mechanized scarification on a volcanic soil after a shelterwood cutting in a Nothofagus spp. forest, located in the Andean region of southern Chile (39° 54 'S, 71° 56' 5 W, 970 m asl). A plantation of Nothofagus nervosa was established after scarification, and its physical (moisture content, bulk density, penetration resistance) and chemical (pH, organic matter, macro and microelements; saturation Al) soil properties were analyzed in scarified gaps and undisturbed forest. The size of N. nervosa planted trees was measured eleven months after their establishment (June 2010). The volumetric water content of the soil was similar with and without scarification (30-50%), regardless of the time of year. The bulk density was higher in the scarified soil when compared to the undisturbed forest. The soil nutrient supply in the gaps (0-20 cm) decreased when compared to the undisturbed forest (0-10 cm), but showed little difference between gaps and between locations within them. The N. nervosa plantation developed properly, with similar growth in gaps of different size. Scarification decreased soil quality; the effects on regeneration will need further evaluation throughout a longer period.

Physiological epicotyl dormancy and recalcitrant storage behaviour in seeds of two tropical Fabaceae (subfamily Caesalpinioideae) species

Physiological epicotyl dormancy in which the epicotyl elongates inside the seed before the shoot emerges has been reported for only a few tropical rainforest species, all of which are trees that produce recalcitrant seeds. In studies on seeds of Fabaceae in Sri Lanka, we observed a considerable time delay in shoot emergence following root emergence in seeds of the introduced caesalpinioid legumes Brownea coccinea and Cynometra cauliflora. Thus, our aim was to determine if seeds of these two tropical rainforest trees have physiological epicotyl dormancy, and also if they are recalcitrant, i.e. desiccation sensitive. Fresh seeds were (i) dried to various moisture levels, and (ii) stored at -1 and 5 °C to determine loss (or not) of viability and thus type of seed storage behaviour (orthodox, recalcitrant or intermediate). To identify the kind of dormancy, we tested the effect of scarification on imbibition and monitored radicle emergence and epicotyl growth (inside the seed) and emergence. FRESH SEEDS OF BOTH SPECIES HAD HIGH MOISTURE CONTENT (MC): 50 % for C. cauliflora and 30 % for B. coccinea. Further, all seeds of C. cauliflora and the majority of those of B. coccinea lost viability when dried to 15 % MC; most seeds of both species also lost viability during storage at -1 or 5 °C. Intact seeds of both species were water permeable, and radicles emerged in a high percentage of them in <30 days. However, shoot emergence lagged behind root emergence by 77 ± 14 days in B. coccinea and by 38 ± 4 days in C. cauliflora. Further, plumule growth inside seeds of C. cauliflora began almost immediately after radicle emergence but not until ∼30-35 days in B. coccinea seeds. Seeds of both species are recalcitrant and have physiological epicotyl dormancy. The kind of physiological epicotyl dormancy in seeds of C. cauliflora has not been described previously; the formula is C(nd) (root)-[Formula: see text] (epicotyl).

Threelobe Morningglory (Ipomoea triloba) Germination and Response to Herbicides

Experiments were conducted in the laboratory and screenhouse to determine the effects of scarification; alternating day/night temperatures; light, salt, and water stress; seed burial depth; and rice residue on seed germination and seedling emergence of threelobe morningglory, and to evaluate the response of this weed to commonly available POST herbicides in the Philippines. Germination was stimulated by seed scarification, suggesting that inhibition of germination in this species is mainly due to the hard seed coat. Germination of the scarified seeds was not influenced by the tested temperatures (alternating day/night temperatures of 25/15, 30/20, and 35/25 C) and light. The concentrations of sodium chloride, ranging from 0 to 250 mM, did not influence germination of the scarified seeds of threelobe morningglory. The osmotic potential required for 50% inhibition of maximum germination was −0.35 MPa, although some seeds germinated at −0.6 MPa. Seedling emergence was greatest for the seeds placed on the soil surface (96%), and emergence declined with increased burial depth in soil. The burial depth required for 50% inhibition of maximum emergence was 2.8 cm. No seedlings emerged from a burial depth of 6 cm or greater. Residues of up to 6 Mg ha−1on the soil surface did not influence seedling emergence of threelobe morningglory. The herbicide 2,4-D at 400 g ai ha−1provided excellent control of threelobe morningglory when applied at the four-leaf (100%) and six-leaf (97%) stages. However, at the eight-leaf stage, percent control was reduced to 67% and herbicide rate had to be increased twofold to achieve 95% control. The information gained from this study could contribute to developing components of integrated weed management strategies for threelobe morningglory. Soil inversion by tillage to bury weed seeds below their maximum depth of emergence and early application of an effective POST herbicide could serve as important tools for managing threelobe morningglory.

Frugivory by Taiwan Barbets (Megalaima nuchalis) and the effects of deinhibition and scarification on seed germination

We investigated the frugivory of Taiwan Barbets ( Megalaima nuchalis Gould, 1863) on passage time and germination of 19 species of commonly consumed fruits, distinguished the deinhibition and scarification effects, and tested if complete bird-gut passage increases seed germination. We measured fruit and seed size and seed retention times (SRTs) and examined the germination of intact fruits and pulp-removed and defecated seeds. Germination latency in intact fruits of most species was prolonged, whereas in more non-figs (7/12), the seed germinability increased after ingestion, and nearly all figs germinated by higher proportions after defecation or depulping. Yet, figs revealed major differences from non-figs. SRTs of both non-figs and figs were negatively dependent on fruit size, which was positively correlated to seed size in non-figs only. The germinability was negatively correlated and the germination onset time was positively correlated with SRTs of the last seeds in non-figs, but neither was correlated with SRTs in figs. Most (14/17) species with germination success were enhanced either by deinhibition and scarification, or the fruits hardly germinated but were aided by pulp removal. Deinhibition revealed greater effects than scarification in increasing the germinability and shortening latency, thus aiding, in particular, non-fig seeds with shorter SRTs or that are often culled during feeding.

Dormancy and germination in Stachys germanica L. subsp. bithynica (Boiss.) Bhattacharjee seeds: Effects of short-time moist chilling and plant growth regulators

We investigated the germination requirements of the species Stachys germanica L. subsp. bithynica (Boiss.) Bhattacharjee (Lamiaceae). We studied the effects of scarification, short-time moist chilling (+4 °C) for 15 and 30 days, and various doses of gibberellic acid (GA 3; 0, 100, 150 and 250 ppm), Kinetin (KIN; 50 ppm) and a combination of 250 ppm GA 3 and 50 ppm KIN. The hormone and moist chilling treatments were carried out under both continuous darkness (20 °C) and photoperiodic (20/10 °C; 12/12 h, respectively) conditions. Seeds failed to germinate in response to short-time moist chilling treatments with distilled water under both continuous darkness and photoperiodic conditions. Seeds were found to have dormancy. Treatments with GA 3 or a combination of GA 3 and KIN were successful at breaking seed dormancy. A maximum of 37% of the seeds germinated after GA 3 application in all series. When only KIN was applied at a 50 ppm concentration, germination (12%) was found only with moist chilling for 30 days under continuous darkness. The highest germination rates were found in seeds treated with combination of 250 ppm GA 3 and 50 ppm KIN. In the combination treatments, while the moist chilling treatments for 15 days resulted in 68 and 73% germination, respectively, these rates were up to 95% in the moist chilling treatments for 30 days under continuous darkness and photoperiodic conditions. Mean germination time (MGT) in GA 3 and KIN combinations was lower than in other treatments. Scarification with 80% sulphuric acid did not promote germination. The characteristics of physiological dormancy of S. germanica ssp. bithynica seeds are consistent with conditions of existence in the in alpine habitat of this species.

Effects of different treatments on seed germination and breaking seed dormancy of Prosopis koelziana and Prosopis Juliflora

For improving seed germination of Prosopis koelziana and Prosopis juliflora, different treatments of seeds were conducted, including scarification with sulfuric acid 98% for 10 and 15 min, sandy paper, hot water for 5 and 10 min, potasium nitrate 0.1%, gibberellic acid at 250 mg·L−1 and 500 mg·L−1 and combinational treatment of scarification with gibberellic acid of 250 mg·L−1 and 500 mg·L−1. The results show that scarifications with sandy paper and sulfuric acids 98% were the most effective treatments on breaking seed dormancy and seed germination induction. Scarification with sulfuric acid 98% for 15 min was the best treatment. According to the positive effect of scarification and lack of reaction of seeds against KNO3 and gibberellic acid, the kind of seed dormancy was determined as exogenous.

Effects of Scarification with Sulfuric Acid and Matric Priming on Seed Germination of Seed Propagation Type of F1 Hybrid Strawberry (Fragaria × ananassa Duch.)

For practical use of the seed propagation type of F1 hybrid strawberry, high germination percentage and germination uniformity are necessary. The effects of scarification with concentrated sulfuric acid and matric priming on seed germination of this strawberry were investigated in order to improve the germination performance. Open-pollinated seeds of ‘Tochiotome’ and seeds from the seed propagation type of the F1 hybrid strawberry cultivar ‘Chiba F-1 go’, bred by ourselves, were used. Germination tests were carried out on a temperature-gradient plate to investigate the response to temperature. The number of germinated seeds was counted for 7 days after sowing. The final germination percentage (FGP) of seeds scarified with 36 N sulfuric acid for 10 min exceeded 83% in the optimal temperature range of around 24–27°C, whereas untreated seeds did not germinate. FGP increased to more than 82% in the wide temperature range of 18–32°C with matric priming in vermiculite (−1.5 MPa) for 12 days after scarification. The effect of scarification time on germination was investigated for the seeds of ‘Chiba F-1 go’. The highest percentage (84%) was obtained in the seeds scarified for 35 min. Furthermore, the germination speed and uniformity increased with extension of the duration of matric priming from 0 to 14 days. Germination performance of the seeds of ‘Chiba F-1 go’ was improved for practical use by scarification with concentrated sulfuric acid and scarification plus matric priming.

Re-establishment rate of reindeer lichen species following conventional disc trenching and HuMinMix soil preparation in Pinus-lichen clear-cut stands: a survey study in northern Sweden

The re-establishment rates of reindeer lichen following conventional soil preparation by disc trenching and gentle soil preparation using HuMinMix apparatus were calculated from data acquired in surveys of 17 Pinus–lichen clear-cut stands in northern Sweden conducted 1–15 years after the treatments. The maximum lichen cover and biomass recorded in areas scarified by disc trenching were 29% and 24% of the lichen cover and biomass measured in adjacent intact lichen mats in the surveyed stands after 15 years. By contrast, 9 years after scarification, the corresponding percentages measured in areas disturbed by the HuMinMix treatment were 91% and 100%, respectively. According to calculated linear regressions, the reindeer lichen cover could be completely re-established just one decade after HuMinMix treatment. Ground lichen diversity in the scarified areas was also inventoried. The significant increase in lichen diversity for HuMinMix, especially of early-successional species, could explain the more rapid re-establishment of late-successional lichens (e.g. Cladonia stellaris spp.), compared with disc trenching. Thus, the study demonstrates that both the degree of initial disturbance and the re-establishment rate of reindeer lichen must be considered when estimating the effects of scarification on lichen loss for reindeer grazing over time.

Effect of Scarification, Self-Inhibition, and Sowing Depth on Seed Germination of Lupinus campestris

Lupinus campestris Schltdl. & Cham. grows in shallow fields and disturbed areas of Central Mexico. It has potential to improve soil fertility and as fodder. Seeds of L. campestris show dormancy, and the technology needed to increase its potential use requires information about conditions favouring seed germination. The aim of this study was to evaluate the seed germination responseof L. campestris under controlled (laboratory) and natural field conditions. Under laboratory conditions, 2 yr old seeds had a maximum germination percentage (50%) when they were scarified with sulphuric acid for 90 min prior to sowing and when laboratory light (0.5 µmol m-2 s-1) was maintained during the diurnal period. Without scarification, only about 3% of the seeds germinated. Light in laboratory resulted in an increased seed germination as compared to darkness condition. In the field experiment 1 yr old seeds were used testing the following treatments: (a) seed scarification (seeds scarified by 30 min immersion in sulphuric acid vs. not scarified), (b) presence or absence of plants of L. campestris in plots before field experiments, and (c) sowing depth (on soil surface and at 3 cm deep). The scarified seeds showed a germination percentage range between 50 and 64%, whereas non-scarified seeds had 9 to 16% germination. The seeds sowed in plots with or without plants of L. campestris (before the experiment) germinated similarly, indicating no evidence of self-inhibition of germination. Three conclusions come out: (1) Scarification treatment with sulphuric acid effectively breaks dormancy in L. campestris seeds; (2) Direct sowing of scarified seeds (on the soil surface or at 3 cm depth) resulted in a range of 50-64% of germination under field conditions; and (3) no evidence was obtained for self-inhibition or a positive interaction between preceding vegetation and seed germination of L. campestris.

Seed viability and effect of scarification with sulphuric acid on germination of Enterolobium contortisiliquum (Fabaceae) seeds

Seed viability and effect of scarification with sulphuric acid on germination of Enterolobium contortisiliquum (Fabaceae) seeds

Stabilité mécanique et caractéristiques racinaires de plants de fortes dimensions de Picea mariana produits en récipients ou à racines nues

In Québec (Canada), large planting stock are used for reforestation of high-competition sites, sometimes in combination with soil scarification. Large conifer seedlings are typically produced in containers &gt;300 cm3, or as bare-root stock. Nursery practices are expected to influence seedling mechanical stability. We measured large containerized and bare-root black spruce (Picea mariana) seedling stability (resistance to winching), and characterized their root architecture, during their seventh growing season since planting in scarified or non-scarified plots devoid of any competing vegetation. We detected no significant stock type or scarification effect on seedling height, diameter, height/diameter ratio, stability, total number of roots and adventive roots. Occurrences of root deformations, as well as vertical and horizontal root distributions, were not influenced significantly by the treatments. The height/diameter ratio was the sole significant predictor of the resistance to winching. Our results indicate that the use of either large containerized or large bare-root stock has limited silvicultural consequences. In this context, the choice of large stock type should be based on other factors, such as handling constraints.Key words: black spruce, reforestation, stock type, scarification, root system

Effects of moist chilling, gibberellic acid, and scarification on seed dormancy in the rare endemic Pedicularis olympica (Scrophulariaceae)

We investigated the germination requirements of a rare endemic plant species, Pedicularis olympica Boiss. (Scrophulariaceae), which grows in wet habitats on Uludag Mountain, Turkey. We studied the effects of scarification, moist chilling (+4 °C) for 15 days, different doses of gibberellic acid (GA3; 100, 150, and 250 ppm) and combined hormone and moist chilling treatments under dark (20 °C) and photoperiod (20/10 °C; 12/12 h, respectively) conditions. GA3 was able to break dormancy. The highest germination rate was found in the seeds treated with 250 ppm GA3; 64% of these seeds germinated when treated with moist chilling and incubated in the dark, while 75% germinated under photoperiod conditions. Moreover, mean germination times were significantly lower in the seeds treated with 250 ppm GA3. Significant differences in final germination percentages and mean germination times were found only for treatments under photoperiod conditions. Scarification also permitted germination; the highest germination rate (78%) was found with 15 min of scarification. Dormancy was not broken by moist chilling for up to 90 days. The germination requirements of dormant P. olympica seeds are found to be consistent with characteristics of its habitat. This can be considered an ecological advantage for the species' establishment and persistence.

Promotion of seed germination in Musa velutina Wendl. & Drude by scarification and GA3

SummarySeeds of Musa velutina Wendl. & Drude contain immature embryos and are unable to germinate under natural conditions. We investigated the effects of scarification and the application of exogenous gibberellic acid (GA3) on seed germination and on -amylase activity in these seeds. Scarification treatments that penetrated the hard seed coat promoted germination of seeds collected at harvest (76.7% germination by 14 d after sowing under aseptic conditions). On the other hand, intact seeds did not germinate under aseptic conditions. The application of GA3 to scarified seeds significantly promoted germination and decreased the number of days until germination. All seeds sown on filter paper moistened with 10 mg l–1 GA3 germinated within 14 d of sowing. GA3 increased the -amylase activity in scarified seeds, whereas application of the GA-biosynthesis inhibitor, paclobutrazol, decreased -amylase activity and resulted in a lower percentage of seed germination. These results indicate that the inability of M. velutina seeds to germinate resulted from the hard seed coat, which inhibited water absorption. Scarification and exogenous GA3 treatments promoted the germination of M. velutina seeds collected at harvest. Moreover, scarification treatment alone may increase the endogenous gibberellic acid content and induce the biosynthesis of -amylase in the embryo.

Influence of Reproductive and Environmental Factors on Population Size of Wild Hyacinth [Camassia angusta (Engelm. and A. Gray) Blank. (Liliaceae)], an Illinois Endangered Species

Wild hyacinth (Camassia angusta) is a perennial species native to mesic prairies of the midwestern and south-central United States. In Illinois, the only extant population of this state-endangered species is in a small section of degraded black-soil prairie along a railroad track right-of-way south of Elwin, Macon County. The objectives of this study were to determine the population status, seed production, and effects of scarification and stratification on germination of C. angusta. The population was surveyed from 1990 to 2007. A survey of other plant species present was conducted in 1999. The site consisted of approximately 75% native and 25% exotic species. The number of flowering stems of Camassia angusta fluctuated significantly (28 to 169 plants) during the course of this study. Prescribed spring burns and a construction equipment disturbance may be partially responsible for these fluctuations. A large percentage of undeveloped fruit, resulting in low seed production (<3,000), as well as low seed germination (8%), may be responsible for this population's inability to increase consistently in number of individuals.

Effect of burial on the germination of Opuntia tomentosa's (Cactaceae, Opuntioideae) seeds

Opuntia tomentosa seeds have physiological dormancy and a permeable but hard funicular envelope that restricts water uptake and embryo growth. Dormancy break, germination, and changes in the funiculus were compared in laboratory-stored seeds and in those buried for 7 months at different microsites and later exhumed and stored in the laboratory. The funicular envelopes of both lots were examined with a scanning electron microscope (SEM). Seeds in both lots were: scarified with H 2SO 4 (0, 45, 60 and 90 min), treated with gibberellins (0, 1000 and 2000 ppm) and germinated at the same ages (0, 2, 4, 7, and 10 months after exhumation) at 24 °C. Light effect was determined at 24 °C and 20–35 °C. In laboratory-stored seeds germination was low. Exhumed seeds germinated in ∼50%, the remaining ones required scarification and gibberellins, but lost dormancy two months later. Gibberellins reduced germination heterogeneity, and scarification reduced germination; the adverse effect of scarification was offset by gibberellins. Exhumed seeds germinated mainly in darkness at 20–35 °C and partially in far red light at both temperatures. SEM showed that fungi eroded the funiculus reducing its resistance. O. tomentosa could form a seed bank, ensuring its survival under heterogeneous environments.