Studies on adaptability of Populus bolleana and other Poplar trees in northwest Shanxi Province

Through five years (1996-2000) experiment, the growth characteristics and resistance to insect and cold of the seven poplar varieties including P. po pularis, P. opera, P. pseudo-simonii, P. beijinensis, P. bolleana, P. ( eurameri cana and P. simonii, which were planted in loess hilly land in northwest Shanxi Province, were tested under different planting densities and site conditions. A randomized block design and three times repetition were adopted in the test. Bas ed on the test results in arid and cold area of the northwest Shanxi, the hybrid poplar trees taking Populus cathaysna as their female parent could be selected for afforestation, such as P. popularis and P. opera, and the growing space of s ingle plant should be larger than 20 m2. P. bolleana as an introduced tree speci es grows well in this area, but its growth is likely affected by ground water co ndition. On the site with relatively abundant soil water, P. bolleana usually su ffer from frost crack at its trunk base. As a result, P. bolleara is suited to p lanting in the site where is short of soil water. P. x euramericana is not suita ble for large-scale afforestation, especially in arid slopes and ridges of loess hilly land .

Analysis of the element content in poplar tree leaves by femtosecond laser-induced breakdown spectroscopy

Femtosecond laser-induced breakdown spectroscopy (fs-LIBS) is employed to analyze the element content in poplar tree leaves from four representative locations in Changchun City (Jingyue National Forest Park,JYP),Changchun University of Science and Technology (CUST),Casting Factory (CF) and Forging Factory (FF) of First Automobile Works (FAW) under identical experimental conditions.Those elements of N,P,K,Ca,Fe,Ti,Mn and Na are identified in the poplar tree leaves from the recorded spectrogram and the elemental content in the leaves is further obtained by applying free calibration method to the spectrogram.Our results show that the elements Ca and Fe in the poplar tree leaves from the CF area have the highest concentration in the four locations,which is a factor of 2.05 and 1.66 respectively to those of JYP.This experiment demon-strates that fs-LIBS can be utilized to analyze element content in a sample and find new applications in the environmental detection.

Comparative analysis of the biodiversity of fungal endophytes in insect-induced galls and surrounding foliar tissue

Insect-induced galls are abnormal plant growths that can provide food and shelter to their inhabitants,resulting in stressed plant tissue that may alter the conditions for the colonization or proliferation of endophytic fungi.We investigated the effect gall formation has on fungal endophyte communities and diversity.Using three closely-related gallforming aphid species that specialize on poplars,we characterized fungal endophyte diversity in galls and surrounding petiole and leaf lamina tissue.A total of 516 fungal endophyte samples were isolated from 272 tissue samples(32 leaves,31 petioles,and 209 galls),resulting in 23 distinct morphotypes.Despite sharing a common host plant and often forming spatially contiguous galls,the endophyte profiles within the galls of each aphid species were distinct,not only from the galls of the other species,but also from surrounding plant tissue.These results suggest that insect galls can affect the composition of fungal endophyte species in plant tissues,by altering either the colonization or proliferation of their endophytic mycobiota.Likewise,fungal endophytes may be important in the ecology and evolution of insect galls.