| Taking the evergreen broad-leaved plants, Machilus pauhoi of subtropical zone in shunchang county and yong’an city, Fujian province as research objects, set different levels of N,P by the way of foliage top-dressing to the plantation. Then took samples in different seasons and different ages to determine their nutrient contents and soil contents to research the influence of foliage spraying to leaf traits,nutrient characteristics and how to respond to the soil nutrient in different ages and the effect of foliage spraying to leaf nutrient resorption efficiency in different seasons. The main results were as follows:(1) The mean SLA, N contents, P contents, moisture content in mature leaves of the age of 4.5,9.5 Machilus pauhoi exceeded those in senesced leaves.At the age of 4.5,the mean SLA of Machilus pauhoi’s mature leaves and senesced leaves were 234.291 cm2/g,104.437 cm2/g, respectively. The mean moisture content were 73.996%,52.040%, respectively. The mean N content were 19.074 mg/g,11.983 mg/g.The mean P content were 1.616 mg/g,0.547 mg/g; At the age of 9.5, the mean SLA of Machilus pauhoi’s mature leaves and senesced leaves were 133.786 cm2/g,117.404 cm2/g, respectively. The mean moisture content were 56.469%,55.258%, respectively. The mean N content were 11.420 mg/g,9.376 mg/g. The mean P content were 0.546 mg/g,0.415 mg/g.(2) The mean N, P contents of the age of 4.5 in mature and senesced leaves both exceeded those in leaves of the age of 9.5; The mean SLA, moisture content in mature leaves of the age of 4.5 exceeded those of the age of 9.5, but those in senesced leaves were less than the age of 9.5.(3)Different level of spraying treatments could improve SLA in mature leaves of the age of 4.5,9.5 and SLA in senesced leaves of the age of 4.5,but reduce SLA in senesced leaves of the age of 9.5;To the moisture content, treatments could improve mature leaves at the age of 4.5,but reduce it in senesced leaves of the age of 4.5 and both mature leaves, senesced leaves of the age of 9.5;To the mean N,P resorption efficiency,treatments could improve both the age of 4.5,9.5.(4)The mean N resorption efficiency of three seasons were 24.01%,16.54%, 17.44%,respectively; The mean P resorption efficiency of three seasons were26.62%, 24.89%,19.66%.P resorption efficiency exceeded N resorption efficiency.Different levels of N, P spraying had significant effects on leaf N, P resorption efficiency except two kinds of fertilizer (low level of N and N, P combined addition, medium level of N and N, P combined addition); There were significant differences between leaves’N, P resorption efficiency of different seasons under different levels of fertilizer (except P addition).N spraying could help vegetation to absorb P efficiently, inversely, P spraying could contribute to absorb N efficiently in growing season; There was a positive relation between N, P resorption efficiency.In different spraying treatments, leaf N, P resorption efficiency were the highest under high level of N and N, P combined addition T15 treatment, (27.12±4.47)%, (27.63±11.97)%, respectively.In different seasons, leaf N, P resorption efficiency were the highest under high level of N and N, P combined addition at June, (26.36±5.03)%, (30.44±11.70)%, respectively.(5) SLA in Machilus pauhoi mature leaves at the age of 4.5 had a significant positive relationship with 0-10 cm soil P content, but there were no significant relationship between SLA in mature leaves of 9.5 and soil nutrient.It showed that the ability to conserve nutrient in the younger Machilus pauhoi was stronger than the older ones. |
PDF Full Text Request