The vegetation in Chaidar valley of Tsinghai province has been classified into alpine steppe, alpine meadow, alpine scrub, swamp meadow and alluvial flat meadow. It is used as a indicator to distinguish the frozen soil. Seasonal frozen soil is usually distributed in alpine steppe. Local appearance of swamp meadow and perennial frozen soil as island is due to the influence of ground water. The perennial frozen soil is mainly distributed in the alpine meadow and alpine scrub. The alluvial flat meadow and seasonal frozen soil are distributed as island or strap along the river due to the influence of water flow. Finelly, their relationships are shown in the key to be used as a reference for related research workers.

According to the observation data in fields during 1975–1976, we studied the redistribution character of solar energy in multi population and suggested the scientific basis and measures for solving the problems of "shading and wind sheltering" in the practice of production. We discussed the problems on' the orientation of planting. On the basis of practice, by the method of mathematic simulation a formula is introduced for identifying the conditions of day light under various planting schemes and given the scientific data for rational population.

We irradiated the medium containing unicellular green alga (Scenedesmus obliquus) with different dosages of Co60 radiation: 8000 r, 12000 r, 24000 r, 32000 r. We added L-cysteine to the algal suspension treated with 16000 r and 32000 r. After treatment, we observed their growth conditions. Observations were made on cell division, cell size, morphological variation and biomass. The results were obtained as follows: 1. Biological effect of the irradiation becomes apparent above 8000 r. 2. The living cells survive only 40% after 4 weeks, therefore LD50 of this alga is about 8000 r to 30 days. 3. In comparison with the higher plants, the effect of Co60 irradiation on the algal cells becomes more apparent in the progeny than in the parent cells. 4. L-cysteine at the concentration of 0.041 mg/ml exerts a marked protective action in reducing the damage due to Co60 irradiation.

Observations were made on the flowering and the seed development of Metasequoia glyptostroboides Hu et Cheng. The materials were collected from 23 (-26) year old trees during 1972–1975 in Nanking. The seed abortion belongs to three categories, which are summarized as follows: 1. the degeneration of nucellus at the early stage of its development; 2. the poor development of the female gametophyte; and 3. the incomplete development of the young embryo. A schedule about the strobili (male and female) and seed development in relation to time is given.

Root nodules of five species of Elaeagnus were studies under the light microscope. Elaeagnus pungens Thunb. and Elaeagnus sp. (introduced from Vietnam) were further investigated by electron microscope. The endophytic organism of Elaeagnus pungens Thunb. has three different developing stages. In the mature nodules, the main form is the vesicle. The hyphae forming the vesicle consist of septate, branching, terminal swollen filaments. The organism appears to be an Actinomycete. In some cases, bacterieid-like cells have also been observed. They might have arisen from the hyphae. The role played by the different forms of the endophyte in symbiotic nitrogen fixation is also discussed.

The absorption spectra of chlorophyll d in different solvents [1,4-dioxane, petroleum ether (b. p. 30–60 ℃), petroleum ether (b. p. 60–90 ℃), ethyl ether, acetone, 80% acetone, benzene, chloroform, carbon tetrachloride, pyridine, carbon sulfide, methylene iodide, methanol, ethanol, 80% ethanol, n-propyl alcohol, iso-propyl alcohol, n-hexyl alcohol, ethanol: acetone (1:1) and ethanol: acetone (2:1)] were studied. The effects of refractive index and dipole moment of organic solvents and water on the red absorption peak of chlorophyll d were discussed.