[Effects of forms and level of nitrogen fertilizer on the content of chlorophyll in leaves of maize seedling].

The level and form of nitrogen fertilizer could significantly influence the growth and development of plant. The present paper studied the content of chlorophyll by the instrument SPAD-502 after treated with different nitrogen fertilizer level and different nitrogen fertilizer form. The results showed that the contents of chlorophyll in the last expanding leaf of maize seedling treated by levels of 0, 100 and 200 kgN x hm(-2) respectively had no significant difference, with the value of SPAD ranging from 43.3 to 43.7, but when the nitrogen fertilizer level got to 400 kgN x hm(-2), the content of chlorophyll in the last expanding leaf of maize seedling increased significantly, which can be caused by other components in the nitrogen fertilizer, which needs to be further studied. The experiments of nitrogen form showed that maize seedling treated by ammonia nitrogen ((NH4)2SO4) contained more chlorophyll than that treated by saltpeter nitrogen (Ca(NO3)2), and the statistical analysis was significant. The reason for the effect of nitrogen form on the content of chlorophyll of maize seedling leaf could be: (1) it is easier for plants to absorb ammonia nitrogen ((NH4)2SO4) than saltpeter nitrogen (Ca(NO3)2); (2) ammonia nitrogen ((NH4)2SO4) contains more trace elements which can promote the growth and development of plants.

[Contents of nutrient elements in NH4(+)-N fertilizer and urea].

Fertilizer contains not only one compound or one element, so it is important to determine the contents of other elements necessitous and beneficial to plant. All the other nutrient elements for plant, including necessitous elements and beneficial elements in ammonia nitrogen fertilizer ((NH4)2SO4) and CO(NH2)2, were analyzed by method of ICP-MS. The results showed that ammonia nitrogen fertilizer ((NH4)2SO4) and CO(NH2)2 both contain many necessitous elements, Mg, P, K, Ca, Mn, Fe, Ni, Cu, Zn and Mo, thereinto the contents of Mg, P, K, Ca, Mn and Fe were on microg x g(-1) the level, and Ni, Cu, Zn and Mo were on the ng x g(-1) level; compared with CO(NH2)2, ammonia nitrogen fertilizer ((NH4)2SO4) contains more necessitous elements and beneficial elements except Mo and Si. All the above elements could influence the results of nitrogen fertilizer efficiency experiments, so pure fertilizer should be used in the future nitrogen fertilizer efficiency experiments and the comparative experiments of different form nitrogen fertilizer.

[Application of ICP-MS to detection of mineral elements and heavy metals in transgenic cotton seeds].

With the rapid development of transgenic cotton, people begin to focus on its physiology and ecology. The present paper studied the contents of heavy metals and microelements in transgenic cotton seeds by ICP-MS/ICP-AES. The results showed that the content of most microelements detected in transgenic cotton seeds, B, Na, Si, P, K, Ca, Mn, Co, Ni, Zn, Se and Mo was lower than that in regular cotton seeds, except Mg, Fe and Cu. And the content of most heavy metals detected in transgenic cotton seeds, Al, As, Cd, Sb, Tl, Pb and Bi, was higher than that in regular cotton seeds, except Cr and Hg. All the data showed that the accumulation of heavy metals and microelements in transgenic cotton seeds is disadvantageous to itself.

Development of a mouse model of arecoline-induced oral mucosal fibrosis.

OBJECTIVE: To develop a BALB/c mouse model of oral submucous fibrosis (OSF) induced by arecoline and to exhibit an accumulation of collagen and angiogenesis changes. METHODS: BALB/c mice were randomly assigned to either the control (distilled water) or experimental group (arecoline) (n = 40). Eight mice from each group were sacrificed every 4 weeks since 8 weeks post treatment. Changes in histopathologic features, levels of collagen type I and collagen type III, and angiogenesis were measured. RESULTS: In the 8th week, epithelium atrophy, collagen cumulation and micrangium pathologic changes in the lamina propria were observed in the oral mucosa. In the 20th week, hyaline degeneration of the connective tissues was observed on the tongue and palate mucosa. The angiogenesis and collagen type I changed significantly as the diseases advanced (P < 0.05); however, collagen type III was not statistically different. CONCLUSIONS: An OSF model involving mice can be rapidly induced by drinking a high-dose of arecoline. OSF angiogenic changes in mice primarily decrease and collagen accumulation is mainly collagen type I.