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.

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.

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.

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.

Identification of a novel seed size associated locus SW9-1 in soybean

Seed size is one of the vital traits determining seed appearance, quality, and yield. Untangling the genetic mechanisms regulating soybean 100-seed weight (100-SW), seed length and seed width across environments may provide a theoretical basis for improving seed yield. However, there are few reports related to QTL mapping of 100-SW across multiple ecological regions. In this study, 21 loci associated with seed size traits were identified using a genome-wide association of 5361 single nucleotide polymorphisms (SNPs) across three ecoregions in China, which could explain 8.12%–14.25% of the phenotypic variance respectively. A new locus, named as SW9-1 on chromosome 9 that explained 10.05%–10.93% of the seed weight variance was found significantly related to seed size traits, and was not previously reported. The selection effect analysis showed that SW9-1 locus has a relatively high phenotypic effect (13.67) on 100-SW, with a greater contribution by the accessions with bigger seeds (3.69) than the accessions with small seeds (1.66). Increases in seed weight were accompanied by increases in the frequency of SW9-1T allele, with >90% of the bred varieties with a 100-SW >30 g carrying SW9-1T. Analysis of SW9-1 allelic variation in additional soybean accessions showed that SW9-1T allele accounting for 13.83% of the wild accessions, while in 46.55% and 51.57% of the landraces and bred accessions, respectively, this results indicating that the SW9-1 locus has been subjected to artificial selection during the early stages of soybean breeding, especially the utilization of SW9-1T in edamame for big seed. These results suggest that SW9-1 is a novel and reliable locus associated with seed size traits, and might have an important implication for increasing soybean seed weight in molecular design breeding. Cloning this locus in future may provide new insights into the genetic mechanisms underlying soybean seed size traits.

Seed Size Effects on Early Seedling Growth and Response to Applied Nitrogen in Annual Ryegrass (<i>Lolium multiflorum</i>L.)

Use of individual plants as experimental units may be necessary when resources are limited, but inter-plant variation risks obscuring differences among treatments. Experiments were undertaken to measure the effects of seed size on seedling size and response to applied nitrogen of annual ryegrass (Lolium multiflorum L.) harvested six or nine weeks after emergence. In two series of experiments, shoot and root dry weights of seedlings increased respectively at means of 53 - 61 and 29 - 30 mg·mg-1 increase in mean seed weight. Between the largest and smallest seed sizes used in this study, there was 83% difference in shoot weight at harvest six weeks after emergence and 22% difference with harvest nine weeks after emergence. Nitrogen (N) application, in comparison, increased shoot dry weights by averages of 69% and 77% with harvests at six or nine weeks, respectively. Dry mass response to N application was similar across seed size categories in shoots or roots. A mean 30% of total seedling-N was retained in roots. Nitrogen utilization efficiency for shoot growth (increase in shoot growth per unit increase in shoot N capture) ranged from 64 mg·mg-1 with harvest six weeks after emergence to 114 mg·mg-1 with harvest at nine weeks after emergence. Delay in seedling harvest from six to nine weeks post-emergence and use of closely-graded seed can reduce variation in individual seedling size and contribute to reduction in random variation in small-scale experiments.

Genetic Variation among <i>Cucurbita pepo</i>Accessions Varying in Seed Nutrition and Seed Size

Pumpkin seed (Cucurbita pepo L.) is a nutritionally valuable food and a significant source of income globally. Pumpkin seeds are rich in oil, protein, unsaturated fatty acids and tocopherols, which are associated with improved human health. Understanding the genetic diversity among pumpkin accessions varying in seed nutrition traits is necessary for designing sound breeding strategies for developing superior cultivars. In the current study, 26 simple sequence repeats (SSR) markers were used to assess genetic relatedness among 29 C. pepo accessions varying in seed oil, seed protein, seed-coat phenotype, seed size and fatty acid composition. The SSR markers revealed 102 alleles averaging 3.92 alleles per loci and mean polymorphic information content (PIC) of 0.44. Eleven of the markers had a PIC of ≥0.5. Ward dendrogram and principle component analysis based on seed traits grouped the genotypes into two major clusters corresponding to subspecies pepo and texana, with all the reduced-hull accessions grouping within the former. Collectively, this data suggests wide phenotypic (seed traits) and genotypic variation within C. pepo that may be exploited to develop superior reduced-hull cultivars.

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.

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.

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.

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.

NARROW AND ROLLED LEAF 2 regulates leaf shape,male fertility, and seed size in rice

Grain yield in rice （Oryza sativa L.） is closely related to leaf and flower development. Coordinative regulation of leaf, pollen, and seed development in rice as a critical biological and agricultural question should be addressed. Here we identified two allelic rice mutants with narrow and semi- rolled leaves, named narrow and rolled leaf2-1 （nrl2-1） and nr12- 2. Map-based molecular cloning revealed that NRL2 encodes a novel protein with unknown biochemical function. The mutation of NRL2 caused pleiotropic effects, including a reduction in the number of longitudinal veins, defective abaxial sclerenchymatous cell differentiation, abnormal tape- tum degeneration and microspore development, and the formation of more slender seeds compared with the wild type （WT）. The NRL2 protein interacted with Rolling-leaf （RL14）, causing the leaves of the nrl2 mutants to have a higher cellulose content and lower Iignin content than the WT, which may have been related to sclerenchymatous cell differentia- tion and tapetum degeneration. Thus, this gene is an essential developmental regulator controlling fundamental cellular and developmental processes, serving as a potential breeding target for high-yielding rice cultivars.

MYB56 Encoding a R2R3 MYB Transcription Factor Regulates Seed Size in Arabidopsis thaliana

Plant seed size is tightly regulated by the development of seed coat, embryo, and endosperm; however, currently, its underlying mechanism remains unclear. In this study, we revealed a regulatory role of an R2R3 MYB transcription factor MYB56 in controlling seed size specifically in Arabidopsis thaliana L. Loss- of-function or knock-down of MYB56 yielded smaller seeds as compared with the wild type. Conversely, overexpression of MYB56 produced larger seeds. Further observation using semi-thin sections showed that myb56 developed smaller contracted endothelial cells and reduced cell number in the outer integument layer of the seed coat during the seed development; by contrast, MYB56 overexpressing lines had expanded endothelial cells and increased cell number in the outer integument layer of the seed coat, suggesting the essential role of MYB56 in regulating seed development. In addition, reciprocal cross- analysis showed that MYB56 affected the seed development maternally. MYB56 was shown to be dominantly expressed in developing seeds, consistently with its function in seed development. Moreover, quantitative reverse transcription polymerase chain reaction analysis revealed that MYB56 regulates the expression of genes involved in cell wall metabolism such as cell division and expansion. Altogether, our results demonstrated that MYB56 represents an unknown pathway for positively controlling the seed size.

EARLY FLOWERING IN SHORT DAYS(EFS) regulates the seed size in Arabidopsis

Post-transcriptional modifications,including histone modifications and DNA methylation,alter the chromatin landscape to regulate gene expression,thus control various cellular processes in plants.EARLY FLOWERING IN SHORT DAYS(EFS)is the major contributor for H3K36 methylation in Arabidopsis and is important for plant development.Here,we find that EFS is expressed in different stages of embryo morphogenesis,and the efs mutant produces larger embryo that results in enlarged seeds.Further analysis reveals that an imprinted gene MOP9.5 is hypomethylated at the promoter region and its expression is derepressed in efs mutant.MOP9.5 promoter is marked by various epigenetic modifications,and we find that following the increase of H3K36me3,H3K27me3 and H3K9me2 levels are reduced in efs mutant.This data indicates an antagonistic regulation between H3K36me3 and DNA methylation,and/or H3K27me3 at MOP9.5.Our results further show that both maternal and paternal EFS alleles are responsible for the seed size regulation,which unraveled a novel function of EFS in plant development.

Effects of fragmentation on the seed predation and dispersal by rodents differ among species with different seed size

Fragmentation influences the population dynamics and community composition of vertebrate animals.Frag­mentation effects on rodent species in forests may,in turn,affect seed predation and dispersal of many plant species.Previous studies have usually addressed this question by monitoring a single species,and their results are contradictory.Very few studies have discussed the fragmentation effect on rodent-seed interaction among tree species with different seed sizes,which can significantly influence rodent foraging preference and seed fate.Given that fruiting periods for many coexisting plant species overlap,the changing foraging preference of ro­dents may substantially alter plant communities.In this study,we monitored the dispersal and predation by ro­dents of 9600 seeds,belonging to 4 Fagaceae species with great variation in seed size,in both the edge and inte­rior areas of 12 tropical forest fragments ranging in area from 6.3 to 13872.9 ha in Southwest China.The results showed that forest fragmentation altered the seed fates of all the species,but the intensity and even the direction of fragmentation effect differed between species with large versus small seeds.For the seeds harvested,frag­ment size showed negative effects in forest interiors but positive effects at edges for the 2 large-seeded species,but showed little effect for the 2 small-seeded species.For the seeds removed,negative effects of fragment size only existed among the small-seeded species.The different fragmentation effect on seed dispersal and predation among plant species may,in turn,translate into the composition differences of the regeneration of the whole fragmented forest.