Research on Rooting Cuttings of Hard Branch of Hippophae rhamnoides

Objective] In order to improve the survival rate of Hippophae rhamnoides hardwood cuttings, cultivate high-quality sea buckthorn seedlings. [Method] This pa-per took hard branches of Russian big fruit H. rhamnoides as material. The days of striking roots, rate of striking roots,root length and number of adventitious root were determined. [Result] The cuttings col ected from upper treetops were obviously inferi-or to the lower ones. Three years cutting is obviously better than one or two years. Cuttings from lower branches were not so good as the cuttings from upper branch-es. Base oblique incisions were clearly superior to paper-cover incision. The optimal length of cuttings was 20-25 cm. The rooting rate of cuttings was the highest by fast dipping with NAA of 50 mg/L. [Conclusion] The study provides theoretical basis for H. rhamnoides artificial cultivation.

Anchorage properties at the interface between soil and roots with branches

Roots play an important role in stabilizing and strengthening soil. This article aims to study the mechanical properties of the interface between soil and roots with branches, using the pullout test method in the laboratory. The mechanical properties of the soil-root with branches interface is determined through the pullout-force and root-slippage curve （F-S curve）. The results of investigating 24 Pinus tabulaeformis single roots and 55 P. tabulaeformis roots with branches demonstrated three kinds of pullout test failures： breakage failure on branching root, breakage failure on branching node, and pullout failure. The branch angle had a remarkable effect on the failure mode of the roots with branches： the maximum pullout force increased with the sum of the branch diameters and the branch angle. The peak slippage and the initial force had a positive correlation with the sum of the branch diameter. The sig- nificance test of correlation between branch angle and the initial force, however, showed they had no correlation. Branch angle and branch root diameter affect the anchorage properties between root system and soil. Therefore, it is important to investigate the anchorage mechanics of the roots with branches to understand the mechanism of root reinforcement and anchorage.

Do root modules still exist after they die?

Background:The terminal branch orders of plant root systems are increasingly known as an ephemeral module.This concept is crucial to recognize belowground processes.However,it is unknown if root modules still exist after they die?Methods:The decomposition patterns of the first five root orders were observed for 3 years using a branch-order classification,a litter-bag method and sequential sampling in a common subalpine tree species(Picea asperata)of southwestern China.Results:Two root modules were observed during the 3-year incubation.Among the first five branch orders,the first three order roots exhibited temporal patterns of mass loss,nutrients and stoichiometry distinct from their woody mother roots throughout the experimental period.This study,for the first time,reported the decomposition pattern of each individual root order and found a similar decomposition dynamic among ephemeral root branches in a forest tree species.Conclusions:Results from this study suggest that root modules may also exist after death,while more data are needed for confirmation.The findings may further advance our understanding of architecture-associated functional heterogeneity in the fine-root system and also improve our ability to predict belowground processes.

Effects of cutting types and hormonal concentration on vegetative propagation of Zanthoxylum armatum in Garhwal Himalaya,India

Experiments were carried out to define the effects of hormonal concentrations on semi-hard wood（SHW） and hard-wood（HW） branch cuttings of the Z.armatum. SHW and HW cuttings were collected in the month of March. The SHW and HW cuttings were treated with different concentration of indole-3-acetic acid and indole-3-butyric acid（IAA and IBA） and placed in vermiculite rooting medium for 90 days under 1-min misting after 10 min. Sprouting, rooting percentage, sprout number, sprout length, root number, and length were measured.The highest rooting and sprouting rate, 64.0 %, was obtained at the 0.3 % IBA treatment in the SHW cuttings.Similarly sprout length and number of roots per cutting were also higher at the 0.3 % IBA treatment in the SHW cuttings. The number of shoots per cutting was higher at the 0.3 % IAA treatment in the SHW cuttings. Root length per cutting was higher in 0.4 % IBA treatment in the SHW cuttings. The results indicated that 0.3 and 0.4 % IBA treatment produce higher rooting percentages as well as the number of roots and their length in SHW cuttings. The HW cuttings produced maximum rate of 18.0 % rooting in0.5 % IBA treatment. The control set and lower concentrations of IBA and IAA completely failed to root in the mist chamber.

Architecter Study of the Young Date Palm （Phoenix dactylifera L.） Root System

The architectural analysis of the young date palm （Phoenix dactylifera L.） root system （its form and its structure）, is necessary to describe its principal functions of absorption and anchoring. In this study the authors present an analysis of the root branching process. It allows them to understand the distribution of inter-lateral root length on the radicle and to account the development of the root system in the soil. Root architecture was studied from samples sprouted naturally in the oases of Chott el Ferikh （Gabes） and other plants grown in polyethylene bags under the shadow. This analysis has showed five categories of roots belonging to four different topological orders in the youthful phasis.

Deep seated magmas and their mantle roots:Introduction

In the last decade there has been a considerable effort to better understand the joint evolution of mafic and ultramafic magmatic systems and their deep mantle roots,through integrated petrological and thermo-barometric studies.Magma generation is regarded as the result of complex processes including melting,creation of channels for melt transfer,and interaction with the wall-rocks.

Root-order-associated variations in fine-root decomposition and their effects on soil in a subtropical evergreen forest

Background:Despite the importance of root decomposition in predicting ecosystem responses to future climate change,the effects of branch order on root decomposition and the feedback to soil still remains poorly understood.Here we separated root samples taken from two tree species(Castanopsis fargesii and Schima superba in subtropical forests along the coastal area in eastern China)into four-order classes(1st–2nd order,3rd order,4th order,and 5th order)and conducted a 540-day litterbag incubation experiment in laboratory to examine root mass loss,nutrient release,and the influence on soil during decomposition.Results:C.fargesii roots of 1st–2nd and 3rd order decayed more slowly than those of 4th and 5th order,but this pattern was not significant for S.superba.Of all the measured root traits,the decomposition rates correlated best with root C/N ratio,diameter and specific root length(SRL)based on the structural equation modeling.Both tree species and root order exhibited significantly effects on root initial traits.Overall,C.fargesii roots decay faster than S.superba,and this appears to be associated with root initial C quality and N concentration.In addition,root order positively affected root decomposition rates mainly through root diameter and SRL.However,no significant difference was found in C and N content between soils below the litterbag with different-order roots.Conclusions:Our findings suggest the effects of branch order on root decomposition are dependent on tree species.Moreover,root morphological properties might also be the controlling factor in root decay besides root chemistry fractions.Overall,the integrative effects should be considered to improve our understanding of the fate of fine-root litter and their contribution to soil C and N pool.