An allelic variation in the promoter of the LRR-RLK gene,qSS6.1,is associated with melon seed size

Seed size is an important agronomic trait in melons that directly affects seed germination and subsequent seedling growth.However,the genetic mechanism underlying seed size in melon remains unclear.In the present study,we employed Bulked-Segregant Analysis sequencing(BSA-seq)to identify a candidate region(~1.35 Mb)on chromosome 6 that corresponds to seed size.This interval was confirmed by QTL mapping of three seed size-related traits from an F2 population across three environments.This mapping region represented nine QTLs that shared an overlapping region on chromosome 6,collectively referred to as qSS6.1.New InDel markers were developed in the qSS6.1 region,narrowing it down to a 68.35 kb interval that contains eight annotated genes.Sequence variation analysis of the eight genes identified a SNP with a C to T transition mutation in the promoter region of MELO3C014002,a leucine-rich repeat receptor-like kinase(LRR-RLK)gene.This mutation affected the promoter activity of the MELO3C014002 gene and was successfully used to differentiate the large-seeded accessions(C-allele)from the small-seeded accessions(T-allele).qRT-PCR revealed differential expression of MELO3C014002 between the two parental lines.Its predicted protein has typical LRR-RLK family domains,and phylogenetic analyses reveled its similarity with the homologs in several plant species.Altogether,these findings suggest MELO3C014002 as the most likely candidate gene involved in melon seed size regulation.Our results will be helpful for better understanding the genetic mechanism regulating seed size in melons and for genetically improving this important trait through molecular breeding pathways.

FGW1, a protein containing DUF630 and DUF632 domains, regulates grain size and filling in Oryza sativa L.

Grain filling influences grain size and quality in cereal crops. The molecular mechanisms that regulate grain endosperm development remain elusive. In this study, we characterized a filling-defective and grain width mutant, fgw1, whose mutation increased rice seed width mainly via cell division and expansion in grains. Sucrose contents were higher but starch contents lower in the fgw1 mutant during the grainfilling stage, resulting in inferior endosperm of opaque, white appearance with loosely packed starch granules. Map-based cloning revealed that FGW1 encoded a protein containing DUF630/DUF632domains, localized in the plasma membrane with preferential expression in the panicle. RNA interference in FGW1 resulted in increased grain width and weight, whereas overexpression of FGW1 led to slightly narrower kernels and better grain filling. In a yeast two-hybrid assay, FGW1 interacted directly with the 14–3–3 protein GF14f, bimolecular fluorescence complementation verified that the site of interaction was the membrane, and the mutated FGW1 protein failed to interact with GF14f. The expression of GF14f was down-regulated in fgw1, and the activities of AGPase, StSase, and SuSase in the endosperm of fgw1increased similarly to those of a reported GF14f-RNAi. Transcriptome analysis indicated that FGW1 also regulates cellular processes and carbohydrate metabolism. Thus, FGW1 regulated grain formation via the GF14f pathway.

BnaUBP15s positively regulates seed size and seed weight in Brassica napus

Brassica napus(B.napus)is a globally significant oilseed crop,making a substantial contribution to both human oil and livestock feed production.Enhancing seed weight is crucial for improving rapeseed yield;however,only a limited number of seed weight-related genes have been functionally validated in B.napus thus far.UBIQUITINSPECIFIC PROTEASE 15(UBP15)belongs to the ubiquitin protease pathway and plays a maternal role in prolonging seed development in Arabidopsis.The potential utilization of UBP15 for enhancing seed yield in B.napus has remained unexplored until now.In this study,we identified the orthologs of UBP15 in B.napus and investigated its functionality using the CRISPR-Cas9 system.We generated mutant plants with multiple editing types targeting Bnaubp15s and successfully isolated T-DNA-free homozygous mutant lines that exhibited edits across four homologs of BnaUBP15 in T2 generation plants.Our preliminary data demonstrated that mutation of BnaUBP15s significantly reduced seed size,seed weight,and plant height while noticeably increasing the number of primary branches.These findings not only provide crucial evidence for further elucidating the molecular mechanism underlying the regulation of seed weight and size by BnaUBP15s but also offer promising novel germplasm for enhancing plant architecture.

Molecular Dissection of Relationship Between Seedling Characteristics and Seed Size in Rice

Seedling characteristics such as leaf emergency, chlorophyll content, and height are important for early growth and also associated with seed size. Quantitative trait loci (QTLs) for rice (Oryza sativa L.) seedling characteristics (leaf length, chlorophyll content, seedling height) and seed size were identified with an attempt to explore the relationship between seedling characteristics and seed size, using a recombinant inbred population derived from a cross between Zhenshan 97A and Minghui 63. Two, one, five, four, four, and nine QTLs were detected for chlorophyll a content, total chlorophyll, length of the second seedling leaf, length of the third seedling leaf, seedling height, and seed size, respectively. The results indicated that four QTLs for seed size and four QTLs for seedling characteristics shared several similar regions (G359-RG532, C567-RG236, RZ403-R19, C371-C405a), respectively, suggesting a close association between seedling characteristics and seed size. Several chromosomal regions influencing seed size, however, had no effects on seedling characteristics, suggesting that it was possible to improve seedling vigor without increasing grain size.

Dormancy heterogeneity among Arabidopsis thaliana seeds is linked to individual seed size

Production of morphologically and physiologically variable seeds is an important strategy that helps plants to survive in unpredictable natural conditions.However,the model plant Arabidopsis thaliana and most agronomically essential crops produce visually homogenous seeds.Using automated phenotype analysis,we observed that small seeds in Arabidopsis tend to have higher primary and secondary dormancy levels than large seeds.Transcriptomic analysis revealed distinct gene expression profiles between large and small seeds.Large seeds have higher expression of translation-related genes implicated in germination competence.By contrast,small seeds have elevated expression of many positive regulators of dormancy,including a key regulator of this process,the DOG1 gene.Differences in DOG1 expression are associated with differential production of its alternative cleavage and polyadenylation isoforms;in small seeds,the proximal poly(A)site is selected,resulting in a short mRNA isoform.Furthermore,single-seed RNA sequencing analysis demonstrated that large seeds resemble DOG1 knockout mutant seeds.Finally,on the single-seed level,expression of genes affected by seed size is correlated with expression of genes that position seeds on the path toward germination.Our results demonstrate an unexpected link between seed size and dormancy phenotypes in a species that produces highly homogenous seed pools,suggesting that the correlation between seed morphology and physiology is more widespread than initially assumed.

The Effect of Seed Size on Phytochemical Composition in Cowpea Lines (<i>Vigna unguiculata</i>(L.) Walp.) from Burkina Faso

The study aimed to determine the effect of seeds size (length, width, thickness and 100 seeds-weight) on their phytochemical composition (total phenolics, total flavonoids, total proteins, soluble sugars and starch) of cowpea accessions (Vigna unguiculata (L.) Walp.) grown in Burkina Faso. The genotypes and their descendants had length, width, thickness and 100 seeds weight between 80 ± 0.7 to 7.40 ± 0.46 cm;6.51 ± 0.41 to 5.76 ± 0.46 cm;5.15 ± 0.37 to 4.22 ± 0.22 cm;12.93 ± 0.09 to 20.16 ± 0.39 g respectively. Total phenol, total flavonoid and starch contents ranged from 585.37 ± 9.73 to 1704.71 ± 4.87 mg GAE per 100 g DW;41.42 ± 2.03 to 52.26 ± 0.75 mg QE per 100 g DW;6.45% ± 0.3% to 46.58% ± 0.12% respectively. The soluble sugars and total proteins contents were ranged respectively from 149.33 ± 3.80 to 432.82 ± 40.81 μg/100mg, and 20.28 ± 0.17 to 27.32 ± 0.17 (%). Seeds size characters had significant and positive correlations with starch content, and significant and negative correlations with total phenolic content. The study of the genetic parameters of phytochemical traits also revealed that they are slightly influenced by the environment. Genetic factors are believed to account for the variation in the observed seed traits, which provides a high potential of studied accessions for breeding programs.

Germination of Encholirium spectabile Mart.ex Schult.&Schult.f.Seeds in Response to Temperature and Water Stress

A study was conducted to examine the effects of different temperatures and water stress on Encholirium spectabile seeds. We evaluated the germination percentage, speed and time of germination of small (4.01 mm), at temperatures of 15°C, 20°C, 25°C, 30°C, 35°C, 40°C and 45°C and a photoperiod of 12 hours of light. Seeds were subjected to osmotic potentials of 0, -0.2, -0.4, -0.6, -0.8, -1.0, -1.2 and -1.4 MPa, induced by solutions of polyethylene glycol. The results indicated an excellent germination of medium and large seeds at the temperatures of 20°C, 25°C, 30°C and 35°C. The temperature of 35°C provided the best mean germination time of large seeds and a higher speed rate of medium and large seeds. E. spectabile seeds germinate in a wide range of water deficit of -0.2 to -1.2 MPa. Germination reduced at concentrations of -1.0 and -1.2 MPa. No germination occurred at -1.4 MPa. Larger seeds showed the higher germination potential than medium and small seeds at the temperatures of 25°C, 30°C and 35°C and in the range ofwater deficit of -0.2 to -1.2 Mpa.

Interaction between seed size and NaCl on germination and early seedling growth of some Turkish cultivars of chickpea(Cicer arietinum L.)

Chickpea is an important food legume crop of Turkey and is largely grown for human consumption on low moisture or salt-affected soils. The objective of the study was to find the effects of NaCl stress at electrical conductivities of 4.5, 8.6, 12.7 and 16.3 dS/m and seed sizes （7, 8 and 9 mm） on germination and early seedling growth of three popular chickpea cultivars （AKN-97, Gokce and Uzunlu-99）. Mean frequency of germination, germination time, germination index, root length, shoot length and seedling fresh weight showed seed size-dependent responses ofcultivars to salt stress. In general, small seeds germinated and grew more rapidly compared to medium and large seeds of the same cultivars against all levels of salt stress, with the best results in cultivar Uzunlu-99. No effect of NaCl treatments was observed on frequency of germination; however, a drastic decrease in early seedling growth was recorded at increased NaC1 concentrations. Regression analysis results showed a significantly positive relationship （P〈0.01） between seed size and mean germination time, whereas a significantly negative relationship was recorded between seed size and germination index, root length, shoot length. Moreover, linear regression values apparently confirmed that increased seed size in each cultivar affected decreased germination index, root and shoot lengths with enhanced mean germination time. Thus, it was concluded that the use of small seeds could considerably reduce the production costs of chickpea in salt-affected soils.

Maternal environment and seed size are important for successful germination and seedling establishment of Pterocarpus erinaceus (Fabaceae)

Seed size and the growth environment are important variables that influence seed germination, growth and biomass of seedlings and future tree harvest and should thus be taken into account in agroforestry and reforestation programmes for endangered species like Pterocarpus erinaceus. In the present study, to assess seedling germination and vigour in P. erinaceus as a function of seed size in two environments, 1080 seeds and 360 seedlings were evaluated at two separate sites in Côte d'Ivoire. The results show that large seeds had very high germination rates (up to 100%) and produced more vigorous plants better able to adapt to climate change. The maternal environment and seed size had a significant influence on seed germination (P < 0.05) and seedling development (P < 0.05) and biomass (P < 0.05). Seedlings were most successful at the site with a humid tropical climate (Daloa). Seedling leaves had the same resistance regardless of seed size and study site, but leaf moisture content was more stable in seedlings grown from medium and small seeds. These results will help guide conservation strategies for the species and are key factors for rural populations, loggers, and forest management structures for the silviculture of this species.

Construction of a high-density adzuki bean genetic map and evaluation of its utility based on a QTL analysis of seed size

Adzuki bean(Vigna angularis(Willd.)Ohwi&Ohashi)is an annual cultivated leguminous crop commonly grown in Asia and consumed worldwide.However,there has been limited research regarding adzuki bean genetics,which has prevented the efficient application of genes during breeding.In the present study,we constructed a high-density genetic map based on whole genome re-sequencing technology and validated its utility by mining QTLs related to seed size.Moreover,we analyzed the sequences flanking insertions/deletions(In Dels)to develop a set of PCR-based markers useful for characterizing adzuki bean genetics.A total of 2904 markers were mapped to 11 linkage groups(LGs).The total length of the map was 1365.0 cM,with an average distance between markers of 0.47 cM.Among the LGs,the number of markers ranged from 208(LG7)to 397(LG1)and the total distance ranged from 97.4 cM(LG9)to 155.6 cM(LG1).Twelve QTLs related to seed size were identified using the constructed map.The two major QTLs in LG2 and LG9 explained 22.1 and 18.8%of the total phenotypic variation,respectively.Ten minor QTLs in LG4,LG5 and LG6 explained 3.0–10.4%of the total phenotypic variation.A total of 9718 primer pairs were designed based on the sequences flanking In Dels.Among the 200 selected primer pairs,75 revealed polymorphisms in 24 adzuki bean germplasms.The genetic map constructed in this study will be useful for screening genes related to other traits.Furthermore,the QTL analysis of seed size and the novel markers described herein may be relevant for future molecular investigations of adzuki bean and will be useful for exploiting the mechanisms underlying legume seed development.

Variations in seed size and seed mass related to tree growth over 5 years for 23 provenances of Quercus acutissima from across China

The origin of a seed strongly impacts its traits, and both origin and seed traits influence seed germination and seedling development. However, in many instances, this effect on the seedling does not persist into adulthood, and little is known about how seed traits and original environment affect seedling/tree growth over time. In this study, seed size, seed mass, seedling/tree growth and origins were collected and determined for 23 provenances of Quercus acutissima from across China. Origin variables correlated well with seed size and seed mass. In stepwise multiple regressions, a longitudinal aridity index explained 49.2-68.7% of the total variation in seed size and mass, while only seed width was correlated with seedling/tree height (H) and diameter at the ground (D) from seed traits and origins. The total variance in H and D explained by the models decreased over time, for example, the R 2 value of the models for H declined from 0.477 in the first year to 0.224 in the fourth year; no models was significant in the fifth year. These results indicate that seed size, regulated by the longitudinal aridity index strongly impacted seedling and tree growth, but the strength of the influence decreased over time, and disappeared after 4 years.

Investigation of Variability in Seed Size on Seedling Establishment of Buchholzia coriacea Engler

Investigation was carried out on the significance of seed size on morphological traits in seedlings of Buchholzia eoriaeea Engler, a medicinal plant in Southwestern Nigeria. Three size classes-large （seeds 〉 40 g）, medium （seeds between 25 and 40 g） and small （seed 〈 25 g） were used. Ninety uniformly growing seedlings from each size class were assessed for shoot height, number of leaves, collar diameter, leaf area and biomass production for six months. Seed size showed significant effect on height growth, collar diameter and number of leaves （P 〈 0.05）. Seedlings from large seed size class had the best height and collar diameter （45.3 cm, 8.7 mm）. Seeds of large and medium seed size classes had overall means of 15.6 and 15.5 leaves/seedling respectively. Leaf dry weight, stem dry weight and root biomass in seedlings from the three seed size classes were significantly different at P 〈 0.05 with the highest mean values for leaf dry weight, stem dry weight and root biomass recorded by seedlings from the large seed size class. The results showed that seed size has great influence on seedling growth when they are young. With availability of sufficient nutrient and light, effect of seed size on seedling growth and development could disappear as seedlings attain maturity.

Influence of the Size of Potato Microtubers (<i>Solanum tuberosum</i>L.) on the Yield of Plants under Semi-Axenic Conditions

The potato (Solanum tuberosum L.) is a vegetable that ranks fifth in the world for human consumption. Its importance is growing more and more in the Senegalese diet. However, the potato production in Senegal does not meet the needs of the market, which maintains dependence on the outside for the supply of quality seeds. In addition, these imported seeds do not often have phytosanitary qualities required for local production in the Sahelian zone. The in vitro production of microtubers, used as seed, has been shown to be one of the most efficient means for propagation of basic material. To overcome the constraints linked to the supply and availability of potato seeds, with high germination capacity, the impact of the microtuber size on the yield of the plants under semi-controlled conditions was examined. The pre-germinated microtubers were produced in vitro from vitroplants of 3 different varieties (Aida, Atlas, Odessa) adapted to the edaphic-climatic conditions of Senegal. The effects of the seed sizes of microtubers, greater than 4 mm, sown under semi-controlled conditions, on the yield of the plants, result in an increase in the ratio, in the vegetative development of the plants, but also in the number and size of the minitubers harvested. The yield of the plants also depends on the variety. It can therefore be envisaged to produce local potato seeds from microtubers and minitubers.

Effect of Seed Sizes on the Growth and Establishment of Seedlings of Sheanut Tree （Vitellaria paradoxa）

Seed size can influence germination, emergence and further development of plants to produce high yield. Therefore, pot trial was conducted to assess the effects of seed sizes on growth and establishment of sheanut tree seedlings （Vitellaria paradoxa） in tlae southern Guinea savanna of Nigeria. Seedlings produced from large sized seed had higher germination （80%） than those from medium （70%） and small （65%） sized seeds. Number of days to emergence of seedling from large-sized seed planting was 30 days, 49 days for small- and medium-sized seeds. Large sized seeds had higher N, P, K, Ca and Mg contents compared with small and medium sized seeds. Generally, seedlings from large sized seeds had about 1.5 times more leaves than medium sized seeds and about 2 times more leaves than small sized seeds at 8, 10, 12, 14 and 16 weeks after planting （WAP）. Seedlings from large sized seeds were taller and had larger stem girth （at 16WAP） than those from medium sized seeds. Variations in seedling growth from seed sizes could be of operational importance in nursery management as seeds can be sown according to size to improve uniformity. However, further studies to ascertain if the superior growth of seedlings from large sized seeds will lead to higher yield is recommended.

Knockout of miR396 genes increases seed size and yield in soybean

Yield improvement has long been an important task for soybean breeding in the world in order to meet the increasing demand for food and animal feed.mi R396 genes have been shown to negatively regulate grain size in rice,but whether mi R396 family members may function in a similar manner in soybean is unknown.Here,we generated eight soybean mutants harboring different combinations of homozygous mutations in the six soybean mi R396genes through genome editing with clustered regularly interspaced palindromic repeats(CRISPR)/CRISPR-associated nuclease(Cas)12SF01 in the elite soybean cultivar Zhonghuang 302(ZH302).Four triple mutants(mir396aci,mir396acd,mir396adf,and mir396cdf),two quadruple mutants(mir396-abcd and mir396acfi),and two quintuple mutants(mir396abcdf and mir396bcdfi)were characterized.We found that plants of all the mir396 mutants produced larger seeds compared to ZH302 plants.Field tests showed that mir396adf and mir396cdf plants have significantly increased yield in growth zones with relatively high latitude which are suited for ZH302 and moderately increased yield in lower latitude.In contrast,mir396abcdf and mir396bcdfiplants have increased plant height and decreased yield in growth zones with relatively high latitude due to lodging issues,but they are suited for low latitude growth zones with increased yield without lodging problems.Taken together,our study demonstrated that loss-of-function of mi R396 genes leads to significantly enlarged seed size and increased yield in soybean,providing valuable germplasms for breeding high-yield soybean.

Modeling Size-number Distributions of Seeds for Use in Soil Bank Studies

Knowledge of soil seed banks is essential to understand the dynamics of plant populations and communities and would greatly benefit from the integration of existing knowledge on ecological correlations of seed size and shape. The present study aims to establish a feasible and meaningful method to describe size-number distributions of seeds in multi-species situations. For that purpose, size-number distributions of seeds with known length, width and thickness were determined by sequential sieving. The most appropriate combination of sieves and seeds dimensions was established, and the adequacy of the power function and the Weibull model to describe size-number distributions of spherical, non-spherical, and all seeds was investigated. We found that the geometric mean of seed length, width and thickness was the most adequate size estimator, providing shape-independent measures of seeds volume directly related to sieves mesh side, and that both the power function and the Weibull model provide high quality descriptions of size-number distributions of spherical, non-spherical, and all seeds. We also found that, in spite of its slightly lower accuracy, the power function is, at this stage, a more trustworthy model to characterize size-number distributions of seeds in soil banks because in some Weibull equations the estimates of the scale parameter were not acceptable.

Germination and early seedling growth of Pinus densata Mast.provenances

We studied seed germination and early seedling growth of Pinus densata to explore the range of variability within the species and to inform afforestation practices. Phenotypes were evaluated at a forest tree nursery under conditions that support Pinus yunnanensis, one of the presumed parental species of P. densata. Seeds were col- lected from 20 open-pollinated trees within each of eight autochthonous populations representing the natural distri- bution of P. densata in China to assess variation in ger- mination traits and early seedling growth, and to examine the relationships among these traits. Results showed that seeds from all populations germinated and seedlings established successfully. There were significant differences among populations in 13 of 14 traits evaluated. Seed germination and early seedling growth were strongly related to seed size and seed weight. Bigger seeds germi- nated earlier and faster than small seeds, and seedling size was positively correlated with seed size. Some germination traits were strongly and significantly correlated with cli- matic variables associated with the provenance of the studied populations. Based on these observations, we conclude there were large, significant, and biologically important differences among P. densata populations in seed germination and seedling growth traits. The observed variability probably reflects a high degree of adaptive dif- ferentiation among populations that is likely to be relevant for future afforestation.

Growth characteristics and reproductive output of dwarf mistletoeinfected Juniperus polycarpos in Iran

Dwarf mistletoes are parasitic flowering plants that infect conifers, resulting in substantial loss of growth and mortality. Recently, forest managers in Iran are contemplating whether infection of Juniperus polycarpos C. Koch forests by dwarf mistletoe, Arceuthobium oxycedri （DC.） M. Bieb, influences tree vigor and contributes to insuffieient natural regeneration. The present study aimed at assessing the severity of infection and its impact on growth and reproductive output of./., polycar- pos. Infected and uninfected trees （n =20 each） were selected for assess- ment of diameter, height, crown area, and crown volume as well as quantity and quality of cones and seeds. The severity of infection of trees was determined by Hawksworth＇s 6-class dwarf mistletoe rating （DMR） system. The DMR system revealed that 40% of the infected sample trees were lightly infected （DMR =1-2） and 60% were moderately infected （DMR =3--4）. Growth characteristics did not differ significantly （p 〉 0.05） between infected and uninfected trees. However, moderate infec- tion affected the reproductive output of./. polycarpos by significantly （p 〈0.05） reducing the mean number of cones per unit area of the crown, increasing the number of damaged seeds, and reducing seed size and seedgermination capacity. We conclude that reproductive output of J.. poly- carpos is more sensitive than growth characters to moderate infection by juniper dwarf mistletoe, and this might partly account for poor natural regeneration.

Overexpression of the MADS-box gene SIMBP21 alters leaf morphology and affects reproductive development in tomato

Fruit yield is the most important horticultural trait of tomato.SIMBP21,a SEPALLATA subclass MADS-box gene has been reported to have functions in regulating pedicel abscission zone identity and development and controlling sepal size in tomato.However,we generated transgenic tomato plants which overexpress SIMBP21 and found the transformants displayed curly leaves,abnormally shaped flowers with twisted and opened stamens,reduced yield parameters,and small and light seeds.Our studies on the gain-of-function phenotype and gene expression level showed that its novel aspects played important roles in determining leaf morphology,flower and inflorescence architecture,and seed size,as well as the fruit yield.Overexpression of SIMBP21 in tomato resulted in curly leaves with fewer leaflets due to the regulation of the critical leaf polarity genes that cause an imbalance between the midvein adaxial-abaxial cell growth.Defects in the architecture of flowers and inflorescences resulted in reduced fruit set.Furthermore,we demonstrated that SIMBP21 plays its role through inhibiting the expression of the genes involved in the determination of seed development in tomato and SIMBP21 protein can interact with other MADS-box protein(SIAGL11,TAGL1 and SIMBP3)to control seed size.Thus,these results suggest that overexpression of SIMBP21 causes multiple types of damage to plant growth and development,especially fruit yield,in tomato.

Conflicting selection pressures on seed size and germination caused by carnivorous seed dispersers

Plants produce nutritious,fleshy fruits that attract various animals to facilitate seed dispersal and recruitment dynamic.Species-specific differential selection of seed size by multiple frugivorous disperser assemblages may affect the subsequent germination of the ingested seeds.However,there is little empirical evidence supporting this association.In the present study,we documented conflicting selection pressures exerted on seed size and germination by five frugivorous carnivores on a mammal-dispersed pioneer tree,the date-plum persimmon(Diospyros lotus),in a subtropical forest.Fecal analyses revealed that these carnivores acted as primary seed dispersers of D.lotus.We also observed that seed sizes were selected based on body mass and were species-specific,confirming the“gape limitation”hypothesis;three small carnivores(the masked palm civet Paguma larvata,yellow-throated marten Martes flavigula,and Chinese ferret-badger Melogale moschata)significantly preferred to disperse smaller seeds in comparison with control seeds obtained directly from wild plants whereas the largest Asiatic black bears(Ursus thibetanus)ingested larger seeds.Seeds dispersed by medium-sized hog badgers(Arctonyx albogularis)were not significantly different from control seeds.However,regarding the influence of gut passage on seed germination,three arboreal dispersal agents(martens,civets,and bears)enhanced germination success whereas terrestrial species(ferret-badgers and hog badgers)inhibited the germination process compared with undigested control seeds.These conflicting selection pressures on seed size and germination may enhance the heterogeneity of germination dynamics and thus increase species fitness through diversification of the regeneration niche.Our results advance our understanding of seed dispersal mechanisms and have important implications for forest recruitment and ecosystem dynamics.