Betula alnoides is a fast-growing hardwood species grown in large plantations in Southeast Asia and South China.Nitrogen requirements for producing robus seedlings,growth and nutrient dynamics were investigated using ...Betula alnoides is a fast-growing hardwood species grown in large plantations in Southeast Asia and South China.Nitrogen requirements for producing robus seedlings,growth and nutrient dynamics were investigated using exponential fertilization treatments.Root collar diameter,height,dry mass and nutrient contents of seedlings increased exponentially in all fertilization treatments as time progressed.Moreover,with water soluble fertilizer（Plant Products plus microelements N–P2O5–K2O：20–20–20）,300 mg N seedling-1was adequate.Vector analysis revealed that P was the most responsive nutrient element followed by N and K.Dilutions of N and K were evident in the plants without N addition,which induced initial P sufficiency and then luxury consumption probably due to the antagonistic interaction between N and P.However deficiencies of N,P and K were mostly observed in al exponential regimes during the experiment because seedling growth rate exceeded nutrient uptake rate,inferring that further study on improving the nutrient uptake efficiency is needed.Analysis of relationships among nutrient supply,dry mass,N content and N concentration demonstrated that 100–400 mg N seedling-1induced sufficiency to luxury consumption of nitrogen without significant change in dry mass,and 400 mg N seedling-1is recommended to apply for nutrient loading of seedlings before outplanting.The findings will help improve seedling quality and enhance the production of robust seedlings for plantation forestry of this species.展开更多
Contamination problems on DNA isolation from 'recalcitrant plant taxa' which is rich in polysaccharides have been commonly encountered in a wide range of research fields such as plant population biology, biodi...Contamination problems on DNA isolation from 'recalcitrant plant taxa' which is rich in polysaccharides have been commonly encountered in a wide range of research fields such as plant population biology, biodiversity, and molecular marker-assisted breeding. Here we present an improved protocol to extract DNA efficiently from dry or fresh leaves of a 'recalcitrant plant taxa', Betula alnoides Buch. Ham. ex D. Don in which three key steps are involved: 1) washing out most of polysaccharides and other secondary compounds with CTAB-free buffer from homogenate; 2) adoption of 3% CTAB rather than 2% CTAB in the exaction medium; and 3) using of high concentration of salt prior to DNA precipitation with isopropanol to remove residual polysaccharides. The isolated DNA has been proved suitable for RAPD-PCR amplification and restriction digestion. This modified procedure is simple, inexpensive and reliable, and is also applicable to many other plant taxa with high polysaccharides.展开更多
基金financially supported by The Ministry of Science and Technology,China(2012BAD21B0102)
文摘Betula alnoides is a fast-growing hardwood species grown in large plantations in Southeast Asia and South China.Nitrogen requirements for producing robus seedlings,growth and nutrient dynamics were investigated using exponential fertilization treatments.Root collar diameter,height,dry mass and nutrient contents of seedlings increased exponentially in all fertilization treatments as time progressed.Moreover,with water soluble fertilizer（Plant Products plus microelements N–P2O5–K2O：20–20–20）,300 mg N seedling-1was adequate.Vector analysis revealed that P was the most responsive nutrient element followed by N and K.Dilutions of N and K were evident in the plants without N addition,which induced initial P sufficiency and then luxury consumption probably due to the antagonistic interaction between N and P.However deficiencies of N,P and K were mostly observed in al exponential regimes during the experiment because seedling growth rate exceeded nutrient uptake rate,inferring that further study on improving the nutrient uptake efficiency is needed.Analysis of relationships among nutrient supply,dry mass,N content and N concentration demonstrated that 100–400 mg N seedling-1induced sufficiency to luxury consumption of nitrogen without significant change in dry mass,and 400 mg N seedling-1is recommended to apply for nutrient loading of seedlings before outplanting.The findings will help improve seedling quality and enhance the production of robust seedlings for plantation forestry of this species.
文摘Contamination problems on DNA isolation from 'recalcitrant plant taxa' which is rich in polysaccharides have been commonly encountered in a wide range of research fields such as plant population biology, biodiversity, and molecular marker-assisted breeding. Here we present an improved protocol to extract DNA efficiently from dry or fresh leaves of a 'recalcitrant plant taxa', Betula alnoides Buch. Ham. ex D. Don in which three key steps are involved: 1) washing out most of polysaccharides and other secondary compounds with CTAB-free buffer from homogenate; 2) adoption of 3% CTAB rather than 2% CTAB in the exaction medium; and 3) using of high concentration of salt prior to DNA precipitation with isopropanol to remove residual polysaccharides. The isolated DNA has been proved suitable for RAPD-PCR amplification and restriction digestion. This modified procedure is simple, inexpensive and reliable, and is also applicable to many other plant taxa with high polysaccharides.
