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Under the background of the mechanical mechanism research of microfluidic technology for separating and screening pipeline particulate matter, this paper proposes an improved relative motion model by combining the multiple reference frame method and the relative motion model. Worked with a quasi-fixed constant method, this model can numerically calculate the aggregation features of non-spherical particles in the low Reynolds number channels. The results demonstrate that when Re = 40~80, ellipsoids exhibit an aggregation trend similar to circular particles with the same diameter as its largest circumscribed sphere. The aggregation position is affected by the ratio of long and short axes of particles, and the distribution trend is determined by the relative size of these particles. When the channel's Reynolds number is less than the critical Reynolds number, the aggregation position of elliptical particles will be closer to the pipe center with the increase in the Reynolds number, which is contrary to the aggregation tendency of circular particles more proximate to the pipe wall with the increase in the Reynolds number. This finding provides a novel idea and method for further exploring the aggregation rules of non-spherical particles and offers substantial guidance for separating and monitoring pipeline particulate matter via microfluidic technology and other related industrial applications.

[Objectives] This study was conducted to provide a reliable theoretical basis for the correct formulation of breeding programs for red-seed watermelon and the effective breeding of hybrid offspring. [Methods] With local varieties and inbred lines of red-seed watermelon as test materials, the generalized heritability of fruit number per plant, single-fruit weight, single-fruit seed number, single-fruit seed weight, seed kernel weight, 1 000-seed weight, kernel--producing ratio, seed production ratio and seed volume were estimated by variance analysis; and the heritability, genetic variation coefficients, and correlation of the nine yield traits in 43 red-seed watermelon varieties were studied. [Results] The generalized heritability of fruit number per plant, single-fruit weight, single-fruit seed number, single-fruit seed weight, seed kernel weight, 1 000-seed weight, kernel--producing ratio, seed production ratio and seed volume were 12. 86%, 80.14%, 75. 96%, 74. 39%, 48. 01%, 17.12%, 24. 97%, 18. 60%, and 37. 07%, respectively. The heritability of single-fruit weight, single-fruit seed number and single-fruit seed weight was higher, and early-generation individual selection could achieve a better effect on them; and 1 000-seed weight and kernel--producing ratio had a higher coefficient of genetic variation, indicating a high selection potential. [Conclusions] Indirect selection could be achieved for traits such as the single-fruit seed number, single-fruit seed weight, seed kernel weight, and seed volume by selecting the single-fruit weight. In the procees of red-seed watermelon breeding, traits with high heritability can be selected in early generations of hybrids, thus playing the role of early-generation orientation. [ABSTRACT FROM AUTHOR]

[Objectives] This study was conducted to explore how to improve the waterlogging tolerance of red-seed watermelon through grafting, to provide a theoretical basis for its cultivation in rainy season. [Methods] The effects of flooding stress on the growth and root physiological and biochemical characteristics of grafted and own-rooted red-seed watermelon seedlings were studied using Luffa as rootstocks and "Zhongxin 1" red-seed watermelon as scions. [Results] After flooding stress, the biomass and root activity of grafted seedlings of red-seed watermelon were significantly higher than those of own-rooted seedlings. With the prolongation of flooding stress time, the soluble sugar and proline content showed a trend of first increasing and then decreasing, and the grafted seedlings had a larger increase and a smaller decrease, and were always significantly higher than own-rooted seedlings in the same period. The content of malondialdehyde in the root system of grafted seedlings increased first and then decreased, while it continued to increase in own-rooted seedlings, and the increase in own-rooted seedlings was significantly greater than that in grafted seedlings during the same period. [Conclusions] Grafting on Luffa rootstocks could improve waterlogging tolerance of red-seed watermelon. [ABSTRACT FROM AUTHOR]

[Objective] This study aimed to establish an appropriate technology system for in vitro screening of Fusarium wilt-resistant germplasm resources of red edible seed watermelon and obtain variants resistant to fusaric acid, thus providing resistant materials for breeding Fusarium wilt-resistant red edible seed watermelon. [Method] Using Zhongxin No. 1 red edible seed watermelon adventitious buds as screening materials and fusaric acid (FA) as a stress agent, in vitro screening of Fusarium wilt-resistant red edible seed watermelon clonal variants and identification of Fusarium wilt-resistance of the germplasm resources of red edible seed watermelon were performed. [Result] The results showed that the appropriate FA for in vitro screening of Fusarium wilt-resistant red edible seed watermelon variants was 15 mg/L. In vitro screening system for Fusarium wilt-resistant red edible seed watermelon variants was established preliminarily and FA-resistant regenerated plants were obtained. Among the 36 germplasm resources of red edible seed watermelon, there were 2 highly resistant materials, 6 moderately resistant materials, 11 slightly resistant materials and 17 highly susceptible materials. [Conclusion] This study confirmed preliminarily that in vitro screening method is effective for obtaining resistant materials of red edible seed watermelon. [ABSTRACT FROM AUTHOR]