Seed Germination of Swertia mussotii,an Important Application in Tibetan Folk Medicine

In this study,the effects of temperature,the growth regulator GA3 and storage conditions on seed germination of the biennial Swertia mussotii Franch were compared in seeds from a natural high altitude alpine site and after one-cycle of artificial cultivation at a low altitude.The untreated seeds from high altitude displayed higher germination than those from low altitude.Both GA3 and storage conditions enhanced germination from all sources.After treatment,the final germination of seeds from different sources shows no distinct difference.These results suggest that:(i) all seeds of this species,irrespective of their sources,have similar kinds of dormancy;(ii) the dormancy of this species can not been broken through one-cycle adaptation in ex situ cultivation and thus might be genetically controlled;(iii) both GA3 and 4℃ cold storage are effective for dormancy breaking in ex situ cultivation of this important medicinal species.

Effects of different seed pretreatments on germination of ten Calligonum species

In order to determine the optimum seed pre??sowing treatments and patterns of germination,a greenhouse experiment was conducted to study the effects of abrasion,sulphuric acid,boiling water,cold stratification and seed exudate treatments on the germination of ten Calligonum species.The results showed that the response of seed germination to the different pretreatments was similar for all ten Calligonum species.The abrasion,sulphuric acid and cold stratification treatments significantly promoted overall germinability.Compared with the control,the exudate treatment significantly decreased the percent germination,hampered the rate of germination and bolstered dormancy for almost all species.The cold stratification treatment can break the dormancy of viable Calligonum seeds and increased the germination,but it has a little lethal effect on viable seeds probably as well as the boiling water treatments.The germinaton patterns performed significant difference between the pre-sowing treatments for all ten Calligonum species,and the speed and percent germination of the Calligonum species can be greatly increased by mechanical scarification or sulphuric acid treatments.The results showed that seeds of C.junceum have strong ability of germinating.

Experimental velocity measurements and effect of flow maldistribution on predicted permeator performances

The shell-side flow distribution of a parallel flow hollow-fiber gas permeator was characterized using a thermo-anemograph. The permeator has an internal diameter of 103 mm and contains 21000 fibers. The overall fiber packing fraction is 40.1%. Experimental results revealed that shell-side flow maldistributions exist in the operating conditions studied. The gas-flow velocity is the highest at the permeator center, but lowest near the shell wall. The effects of shell-side flow maldistribution on predicted permeator performances are discussed with a simple model. Model calculation results show that flow maldistributions can have considerable effect on permeation systems with relatively high separation factors and stage cuts. (C) 1998 Elsevier Science B.V.

A velocity map ion-imaging study on ketene photodissociation at 208 and 213 nm: Rotational dependence of product angular anisotropy

Photodissociation dynamics of ketene following excitation at 208.59 and 213.24 nm have been investigated using the velocity map ion-imaging method. Both the angular distribution and translational energy distribution of the CO products at different rotational and vibrational states have been obtained. No significant difference in the translational energy distributions for different CO rotational state products has been observed at both excitation wavelengths. The anisotropy parameter beta is, however, noticeably different for different CO rotational state products at both excitation wavelengths. For lower rotational states of the CO product, beta is smaller than zero, while beta is larger than zero for CO at higher rotational states. The observed rotational dependence of angular anisotropy is interpreted as the dynamical influence of a peculiar conical intersection between the B-1(1) excited state and (1)A(2) state along the C-S-I coordinate.