Regulation of soybean stem growth habit:A ten-year progress report

Stem growth habit dictates plant architecture and influences flowering and podding(seed setting),making it an essential morphological and breeding agronomic trait of soybean(Glycine max).Stem growth habit in soybean is affected by photoperiod and environment and is determined by genetic variation at major genes.Classical genetic analysis identified two critical loci,designated Determinacy 1(Dt1)and Determinacy 2(Dt2).Dt1 is an ortholog of Arabidopsis thaliana TERMINAL FLOWER1(TFL1)and specifies an indeterminate stem growth habit,whereas Dt2 specifies a semi-determinate growth habit.MADS-box proteins,including Dt2,SUPPRESSOR OF OVEREXPRESSION OF CO1(GmSOC1)and MADS-box genes downregulated by E1(GmMDE),repress Dt1 expression.Photoreceptors encoded by the E3 and E4 loci regulate the expression of soybean FLOWERING LOCUS T(GmFT)orthologs via circadian clock genes and E1,and GmFTs compete with Dt1 to regulate stem growth habit.Study of the molecular mechanism underlying the regulation of stem growth habit in soybean has focused on the repression of Dt1 expression.Here we provide an overview of progress made in elucidating the genetic and molecular bases of stem growth habit in soybean,with emphasis on the molecular components responsible for integrating photoperiodic flowering and stem growth habit.

Effects of Corticosterone, cAMP, cGMP, Ca^(2+), and Protein Kinase C on Apoptosis of Mouse Thymocytes Induced by X-ray Irradiation

Objective To observe the effects of signal factors of corticosterone （CS）, cAMP, cGMP, Ca^2＋ and protein kinase C （PKC） on lymphocyte apoptosis in mouse thymus induced by X-rays of 4 Gy in vitro. Methods The DNA lyric rate for thymocytes was measured by fluomspectrophotometry. Results The DNA lyric rate for thymocytes 4-8 hours after irradiation with 2-8 Gy was significantly higher than that in the control （P〈0.01）. As compared with the control, the DNA lyric rate for thymocytes treated with 0.01 μnol/L CS （P〈0.01）, 50 ng/mL cAMP （P〈0.01）, 0.05-0.4 μg/mL ionomycin （Iono, P〈0.05 or P〈0.01） or 0.05-0.4 ng/mL phorbol myristate acetate （PMA, P〈0.05 or P〈0.01）, respectively, was significantly increased, while the rate for thymocytes treated with 50 ng/mL cGMP was not significantly increased. The DNA lyric rate for thymocytes treated with 0.01 μmol/L CS （P〈0.01）, 50 ng/mL cAMP （P〈0.01）, 0.2 and 0.4 μg/mL Iono （P〈0.05）, and 0.2 and 0.4 ng/mL PMA （P〈0.05） plus 4-Gy irradiation, respectively, was significantly higher than that treated with single 4-Gy irradiation, while the rate for thymocytes treated with 50 ng/mL cGMP plus 4-Gy irradiation was not increased. When both 0.4 I.tg/mL Iono and 0.4 ng/mL PMA acted on the thymocytes, the DNA lyric rate for thymocytes was significantly higher than that in the control （P〈0.01）, the DNA lytic rate for thymocytes treated with both 0.4 μg/mL Iono and 0.4 ng/mL PMA plus 4-Gy irradiation was significantly higher than that treated with single 4-Gy irradiation （P〈0.05）, but was Iono plus 4-Gy irradiation or 0.4 ng/mL PMA plus 4-Gy irradiation. can promote thymocyte apoptosis induced by larger dose X-rays. not significantly higher than that treated with 0.4 μg/mL Conclusion CS, cAMP, Ca^2＋, and PKC signal factors can promote thymocyte apoptosis induced by larger dose X-rays.

Ultrafast magnetization enhancement and spin current injection in magnetic multilayers by exciting the nonmagnetic metal

A systematic investigation of spin injection behavior in Au/FM(FM=Fe and Ni)multilayers is performed using the superdiffusive spin transport theory.By exciting the nonmagnetic layer,the laser-induced hot electrons may transfer spin angular momentum into the adjacent ferromagnetic(FM)metals resulting in ultrafast demagnetization or enhancement.We find that these experimental phenomena sensitively depend on the particular interface reflectivity of hot electrons and may reconcile the different observations in the experiment.Stimulated by the ultrafast spin currents carried by the hot electrons,we propose the multilayer structures to generate highly spin-polarized currents for the development of future ultrafast spintronics devices.The spin polarization of the electric currents carried by the hot electrons can be significantly enhanced by the joint effects of bulk and interfacial spin filtering.Meanwhile,the intensity of the generated spin current can be optimized by varying the number of repeated stacking units and the thickness of each metallic layer.