Mao Zijun

Significance of the leaf epidermis fingerprint for taxonomy of Genus Rhododendron

Leaf epidermal fingerprints of six species of Rhododendron (Rh. Aureaum, Rh. dauricum, Rh. micranthum, Rh. Mucronulatum, Rh. Redowskianum, Rh. schlippenbachii) were observed by optical microscope with nail polish expression method in Key Laboratory of Forest Plant Ecology of Ministry Education China in Northeast Forestry University in 2004. The leaf morphological features including of stomata types, characters of guard cells, subsidiary cells in lower epidemis were observed. And ordinary cells (in shape and anticlinal walls feature) as well as the trichomes in both sides of the leaves are described in detail. The results showed that there were three types of stoma in six investigated Rhododendron species, from which Pericytic stomata type exists in three species (Rh. dauricum, Rh. micranthum, and Rh. mucronulatum), Anomocytic stomatal type in Rh. Redowskianum, Diacytic stomata type in Rh. aureaum and Rh. schlippenbachii. The subsidiary cells of the Pericytic and Diacytic stomata type are different in shape and surface feature between the species, respectively. The ordinary epidermal cells show a variety from quadrangular to hexagonal, polygonal or irregular in surface view, the anticlinal walls are straight or sinuose. Trichomes (gland scales) are present in the both of the leaf sides in three species (Rh. dauricum, Rh. micranthum, and Rh. mucronulatum). All of these detail leaf features show specific specificity of leave finger print for 6 rhododendrons.

Space-time dynamics of fine root biomass of six forests in the Maoershan forest region, northeast China

The Maoershan forestry centre is situated in the Zhangguangcai Mountain of the Changbai mountain range. The main forest types in the Maoershan region are plantation (Pinus sylvestris var. mongolica, Pinus koraiensis and Larix gmelinii) and natural secondary forests (Fraxinus mandshurica, Quercus mongolica and Populus davidiana). Fine roots have enormous surface areas, growing and turning over quickly, which plays an important role in terms of substance cycling and energy flow in the forest ecosystem. This study deals with the dynamics of live, dead, and total fine roots (≤ 5 mm) biomass in the 0–30 cm soil layer using the soil core method. Differences between the six stands in the Maoershan region showed the following results: 1) the fine root biomass in the various stands showed obvious differences. The total fine root biomass of six stands from high to low were F. mandshurica (1,030.0 g/m2) > Q. mongolica (973.4 g/m2) > Pinus koraiensis (780.9 g/m2) > L. gmelinii (718.2 g/m2) > Populus davidiana (709.1 g/m2) > Pinus sylvestris var. mongolica (470.4 g/m2); 2) except for L. gmelinii, the development of live fine root biomass agreed with the trend of total fine root biomass. The maximum biomass of live fine roots in Pinus koraiensis or L. gmelinii stand appeared in May, others in June; in the F. mandshurica stand, the minimum biomass of live fine roots occurred in September, others in July or August; 3) the proportions of dead fine root biomass varied in different stands; 4) the vertical distribution of fine roots was affected by temperature, water, and nutrients; the proportion of fine root biomass was concentrated in the 0–10 cm soil layer. The fine root biomass of six stands in the 0–10 cm soil layer was over 40% of the total fine root biomass; this proportion was 60.3% in F. mandshurica. Space-time dynamics of the various stands had different characteristics. When investigating the substance cycling and energy flows of all forest ecosystems, we should consider the characteristics of different stands in order to improve the precision of our estimates.

Reproductive strategies and seeds behavior ofBetula platyphylla Suk. population

By the methods of morphological anatomy and investigation in the sample fields, the main studies were carried out such as morphological anatomy of reproductive organs, birch population’s reproductive ages, reproductive allotment value and seed behavior. The relationship between birch population and their surroundings was studied. The results showed that birch’s flower organs and its seeds were suitable well for spreading by wind. The seeds by wind can fly far away in a short time. The quantity of seed spreading greatly varied with different communities. Birch’s reproduction age can be changed in different ecological surroundings. The reproductive allotment value of birch was obviously different at different reproductive stages. In the mesic habitat, birch can grow well. The lowest reproductive age of them was 12, average age 15. In most cases the age of branches to bearing fruits was more than 18. The order of reproductive allotment values was as follows: a flowering phase > flower bud phase > fruit phase.

Effects of Methylated Soybean Oil Adjuvant on Fomesafen Efficacy to Weeds

Abstract Tank-mix adjuvant has the potential to improve the weed control efficacy of post-emergence herbicides. In order to study the synergistic effect of adjuvant, the effects of different rates of fomesafen alone or applied methylated soybean oil adjuvant (MSO) were sprayed on redroot pigweed, abutilon and black nightshade under greenhouse condition. The results showed that fomesafen had different performance on the three weeds, and MSO adjuvant could effectively increase the control. The nightshade control was lower than other two weeds with all the fomesafen doses from 131.25 to 506.25 ga.i. • hm -2 with or without adjuvant. The control of abutilon was between the black nightshade and the redroot pigweed, and had better control at 375 ga.i. • hm -2 with adjuvant or 506.25 ga.i. • hm -2 alone or with adjuvant respectively. The results indicated that mixing adjuvant with fomesafen improved the control on weeds, especially at the low rate. Black nightshade was more difficult to control. The redroot pigweed had the most susceptibility to fomesafen alone or with adjuvant.