Activities of some defense proteins associated with age or plant family in larch needles of Larix olgensis and L. kaempferi× L. gmelinii

Defence proteins are a kind of chemical defence compounds. They play a key role in plant restraining biotic and abiotic harm. To illuminate activities of some defense proteins associated with age or plant family of larch, the larch needles were collected from two different families of Korean larch, Larix olgensis and a hybrid larch, L. kaempferi × L. gmelinii, respectively, and then the activities of defence proteins in those were tested using a UV spectrophotometry. The results showed that the activities of protective enzymes at thel6-/17- and 19-year-age groups were higher than those at the other age groups in the both larch species. While the activities of polyphenol oxidase （PPO） at the 16-/17-year-age group and phenylalanine ammonia-lyase （PAL） and protease inhibitors at the 19-year-age group were the highest among all age groups. Then, compared with L. olgensis, the hybrid larch had significant effects on the activities of protective enzymes. The effects of plant family on the activities of PAL and chymotrypsin inhibitor were significantly different, and then those on the activities of PPO were not significantly different. The effects of the two families in L. olgensis on the activities of trypsin inhibitor （TI） were significantly different, while those in the hybrid larch on the activities of TI were contrary. To conclusions showed that the different age and plant family significantly affected the activities of defence proteins in the needles of two larch species, and then enhanced the larch resistance to pests. These could play a key function in forestry tree genetic improvement and management in future.

Stabilizability analysis of sphere plants

Let P（s, δ） be a sphere plant family described by the transfer function set where the coefficients of the denominator and numerator polynomials are affine in a real uncertain parameter vector δ satisfying the Euclidean norm constraint ｜｜δ｜｜〈δ. The concept of stabilizability radius of P（s, δ） is introduced which is the norm bound δs for δ such that every member plant of P（s, δ） is stabilizable if and only if ｜｜δ｜｜〈δs. The stabilizability radius can be simply interpreted as the ＇largest sphere＇ around the nominal plant P（s,θ） such that P（s, δ） is stabilizable. The numerical method and the analytical method are presented to solve the stabilizability radius calculation problem of the sphere plants.

Stability margin of uncertain control systems

Achieving stability is the essential issue in the control system design. In this paper, four approaches that can be used to calculate the stability margin of the interval plant family are summarized and compared. The μ approach gives the bounds of the stability margin, and good estimation can be obtained with the numerical method. The eigenvalue approach yields accurate value, and the MATLAB＇s function robuststab sometimes provides wrong results. Since the eigenvalue approach is both accurate and computationally efficient, it is recommended for the calculation of the stability margin, while utilization of the function robuststab should be avoided due to the unreliable results it gives.

RESEARCH OF COMPLEX AND BIOACTIVE TERPENOIDS FROM MEDICINAL PLANTS OF MELIACEAE FAMILY

In China,many plants of Meliaceae,distributed mainly in Southern China,were well-known Chinese folk medicines using to treat dysentery and fever.Recently,plants from Meliaceae were the research focus of natural products because of their diverse structures and interesting biological properties.In order to discover novel and bioactive natural products from Chinese folk medicinal plants,we have investigated the chemical constituents and bioactivity