Ammonium （NH4^＋） is an important form of nitrogen nutrient for most plants, yet is also a stressor for many of them. However, the primary events of NH4^＋ toxicity at the cellular level are still unclear. Here, we ...Ammonium （NH4^＋） is an important form of nitrogen nutrient for most plants, yet is also a stressor for many of them. However, the primary events of NH4^＋ toxicity at the cellular level are still unclear. Here, we showed that NH4^＋ toxicity can induce the root cell death in a temporal pattern which primarily occurs in the cells of root maturation and elongation zones, and then spreads to the ceils in the meristem and root cap. The results from the NH4^＋-hypersensitive mutant hsn1 further confirmed our findings. Taken together,NH4^＋ toxicity inhibits primary root growth by inhibiting cell elongation and division and inducing root cell death.展开更多
本文分析了三套(T、C、S、N)与20对(C、N)玉米同核异质系,在25℃条件下,经 C 毒素(HMC)处理3小时后,观察根冠细胞的死亡率。结果表明,C 细胞质的细胞死亡率均高于其它同核异质系。因此,C 毒素对 C 细胞质的毒害作用是特异性的,同时也为...本文分析了三套(T、C、S、N)与20对(C、N)玉米同核异质系,在25℃条件下,经 C 毒素(HMC)处理3小时后,观察根冠细胞的死亡率。结果表明,C 细胞质的细胞死亡率均高于其它同核异质系。因此,C 毒素对 C 细胞质的毒害作用是特异性的,同时也为快速鉴定玉米雄花不育细胞质提供了一种新方法。展开更多
Root border cells （RBCs） originate from the root tip epidermis and surround the root apices. In this study, we evaluated the developmental characteristics and the roles of RBCs in protection of root apices of cucumb...Root border cells （RBCs） originate from the root tip epidermis and surround the root apices. In this study, we evaluated the developmental characteristics and the roles of RBCs in protection of root apices of cucumber and ifgleaf gourd seedlings from CA toxicity. The formation of RBCs and the emergence of the root tip occurred almost simultaneously in root apices of cucumber and ifgleaf gourd seedlings. CA ranging from 0 to 0.25 mol L-1 inhibited root elongation and decreased root cell viability in the root tip, moreover the inhibitory effects of CA were more signiifcant in the CA-sensitive cucumber than in the CA-tolerant ifgleaf gourd. Removal of RBCs from root tips led to more severe CA induced inhibition of root elongation and decline in root cell viability. Increasing CA levels and treatment time decreased the relative viability of attached and detached RBCs. CA also induced a thicker mucilage layer surrounding attached RBCs of both species. Additionally, a signiifcantly higher relative cell viability of attached RBCs and thicker mucilage layers were observed in ifgleaf gourd. These results suggest that RBCs play an important role in protecting root tips from CA toxicity.展开更多
The effects of various rare earth elements on growth and isoflavonoid production in hairy root cultures of Pueraria lobata (Willd.) Ohwi (strain TR2) cultured in 500 ml flasks were studied. After 32 days of culture, t...The effects of various rare earth elements on growth and isoflavonoid production in hairy root cultures of Pueraria lobata (Willd.) Ohwi (strain TR2) cultured in 500 ml flasks were studied. After 32 days of culture, the biomass of hairy roots increase 15 times and reach 3.2 g dry weight. Hairy root growth was inhibited by Y_2O_3, NaSeO_3 and Sm^(3+) because of brown formation. But significant promoting effect on root growth due to callus formation was observed in La^(3+) treatments. It is the most noteworthy that the production of total isoflavonoids and puerarin was enhanced greatly by La^(3+) treatment. A major portion of increased total isoflavonoids and puerarin was released into medium in La^(3+) treatment while the hairy root viabilities were preserved. Some specific secondary metabolite release processes could be induced by La^(3+) and their possible mechanism is discussed.展开更多
基金Project supported by the National Basic Research Program (973) of China (No.2005CB120901)the China Postdoctoral Science Foundation (No.20090451463),the China Postdoctoral Special Foundation (No.201003729)
文摘Ammonium （NH4^＋） is an important form of nitrogen nutrient for most plants, yet is also a stressor for many of them. However, the primary events of NH4^＋ toxicity at the cellular level are still unclear. Here, we showed that NH4^＋ toxicity can induce the root cell death in a temporal pattern which primarily occurs in the cells of root maturation and elongation zones, and then spreads to the ceils in the meristem and root cap. The results from the NH4^＋-hypersensitive mutant hsn1 further confirmed our findings. Taken together,NH4^＋ toxicity inhibits primary root growth by inhibiting cell elongation and division and inducing root cell death.
基金supported by the National Basic Research Program of China(973 Program2009CB1190002)the National Key Technology R&D Program of China(2011BAD12B01)
文摘Root border cells （RBCs） originate from the root tip epidermis and surround the root apices. In this study, we evaluated the developmental characteristics and the roles of RBCs in protection of root apices of cucumber and ifgleaf gourd seedlings from CA toxicity. The formation of RBCs and the emergence of the root tip occurred almost simultaneously in root apices of cucumber and ifgleaf gourd seedlings. CA ranging from 0 to 0.25 mol L-1 inhibited root elongation and decreased root cell viability in the root tip, moreover the inhibitory effects of CA were more signiifcant in the CA-sensitive cucumber than in the CA-tolerant ifgleaf gourd. Removal of RBCs from root tips led to more severe CA induced inhibition of root elongation and decline in root cell viability. Increasing CA levels and treatment time decreased the relative viability of attached and detached RBCs. CA also induced a thicker mucilage layer surrounding attached RBCs of both species. Additionally, a signiifcantly higher relative cell viability of attached RBCs and thicker mucilage layers were observed in ifgleaf gourd. These results suggest that RBCs play an important role in protecting root tips from CA toxicity.
文摘The effects of various rare earth elements on growth and isoflavonoid production in hairy root cultures of Pueraria lobata (Willd.) Ohwi (strain TR2) cultured in 500 ml flasks were studied. After 32 days of culture, the biomass of hairy roots increase 15 times and reach 3.2 g dry weight. Hairy root growth was inhibited by Y_2O_3, NaSeO_3 and Sm^(3+) because of brown formation. But significant promoting effect on root growth due to callus formation was observed in La^(3+) treatments. It is the most noteworthy that the production of total isoflavonoids and puerarin was enhanced greatly by La^(3+) treatment. A major portion of increased total isoflavonoids and puerarin was released into medium in La^(3+) treatment while the hairy root viabilities were preserved. Some specific secondary metabolite release processes could be induced by La^(3+) and their possible mechanism is discussed.
