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A series of homogeneous AgGa(S1−xSex)2 solid solution nanocrystals with controllable composition (0 ≤ x ≤ 1) have been successfully prepared through a facile colloidal synthesis approach. Remarkably, they exhibit an evident crystal phase transformation from orthorhombic to tetragonal along with the chemical composition of particles from either S or Se excess to S/Se approximate equality. The factors to determine this phase-selective synthesis of AgGa(S1-xSex)2 nanocrystals could be probably attributed to the relatively weak reactivity of Ga3+ in the oleylamine-based reactive system and the metastable terminal possessed by AgGa(S1-xSex)2, which was proposed after investigating their nucleation mechanisms. Furthermore, the photocatalytic potential of the as-synthesized AgGa(S1−xSex)2 nanocrystals has been evaluated through degrading methyl violet under visible-light illumination. Benefiting from the optimized crystal phase and energy structure, AgGa(S0.7Se0.3)2 presents the optimal photocatalytic efficiency of 88.48%. [ABSTRACT FROM AUTHOR]

Main conclusion: Natural 2n female gametes and transmission of parental heterozygosity by natural 2n gametes in Populus tomentosa are reported for the first time, which provides a new approach to polyploid breeding.Abstract: Naturally occurring 2n pollen is widespread in Populus tomentosa and plays an important role in polyploid breeding. However, the competitiveness of 2n pollen is lower than that of haploid pollen during pollination and fertilization, so 2n pollen is less efficient at fertilizing haploid female gametes to produce polyploids. In theory, polyploids can also be obtained when 2n female gametes are fertilized by haploid pollen. Thus, the question becomes whether natural 2n female gametes exist in P. tomentosa, which can be answered by examining the genetic composition of natural 2n gametes. In this study, the origin of 87 triploids from the hybrid combination “X-2 × Z-5” was identified by SSR markers and 21% of natural 2n gametes were found to originate from female parents. Four SSR loci with low recombination rates were used to identify the genetic composition of natural 2n gametes. The results showed that the genetic composition of 2n female gametes was mainly characterized by SDR, while 2n male gametes were mainly produced by FDR. Moreover, the transmission of parental heterozygosity by natural 2n gametes, which is significantly different between female and male parents in FDR and SDR types, was analysed using 42 SSR primers. Here, we report naturally occurring 2n female gametes for the first time in P. tomentosa and reveal the genetic constitution and transmitted parental heterozygosity of these gametes. Our results provide a foundation for theoretical research into 2n gametes and their application in new polyploid breeding strategies. [ABSTRACT FROM AUTHOR]