Symbiotic nitrogen fixation in black locust (Robinia pseudoacacia L.) seedlings from four seed sources

We conducted a greenhouse experiment to investigate the role of seed source in growth and symbiotic nitrogen fixation of black locust （Robinia pseudoacacia L）. Seeds from different sources were planted in the same environmental conditions and inoculated with a suspension of mixed Rhizobium. We used the modified ^15N isotope dilution method to estimate biological nitrogen fixation of Robinia trees. Different Robinia seed sources differed significantly in terms of tissue dry weight （50.6-80.1 g）, total N （1.31-2.16 g） and proportion of nitrogen derived from the atmosphere （ 0-51%）. A higher nitrogen fixation rate of Robinia trees was associated with higher dry weight. Moreover, the leaves of Robinia proved to adequately represent the nitrogen fixation capacity of entire plants. Our results confirmed that assessment of seed sources is a useful way to improve the nitrogen fixation capacity and therefore the growth rate of Robinia.

灰盖鬼伞原基发育过程中的蛋白质组变化

灰盖鬼伞在25℃以及12 h光照/12h黑暗的环境下形成子实体。子实体最初在黑暗环境下通过大量生产菌丝分支形成初级菌丝结。光照信号触发初级菌丝结开始形成紧密的二级菌丝结。在随后原基发育的5 d中,菌盖和菌柄开始按照不同的光调控模式从这些菌丝结中分化,然后在第6天成熟。为了了解菌盖和菌柄组织形成时复杂的细胞过程,提取了原基各期的蛋白质组进行MS/MS质谱分析。结果显示,在不同的样本中检测到大约1672~2663个至少具有2个肽的蛋白,其中1401个蛋白是所有样本共有的,其中包含已知的涉及原基发育的蛋白。