[Analysis of inorganic elements in hydroponic Taraxacum mongolicum grown under different spectrum combinations by ICP-AES].

Dandelion (Taraxacum mongolicum) was hydroponically cultured in a completely enclosed plant factory, in which fluorescence and LED emitting spectra of different bands were used as the sole light source for plant growth. Effects of spectral component on the growth of dandelion were studied and the contents of ten inorganic elements such as K, P, Ca, Mg, Na, Fe, Mn, Zn, Cu and B in dandelion were analyzed by ICP-AES technology. The results showed that: (1) Under the condition of similar photosynthetic active radiation (PAR), single R or combined spectrums of FLRB were beneficial for biomass accumulation, while single B was the contrary; (2) Macroelements content ratio in Taraxacum mongolicum grown under FLwas K:Ca:P:Mg : Na=79.

[Effects of LED spectrum combinations on the absorption of mineral elements of hydroponic lettuce].

Lettuce (Lactuca sativa) was hydroponically cultured in a completely enclosed plant factory, in which spectrum proportion-adjustable LED panels were used as sole light source for plant growth. Absorption and content of eleven mineral elements such as K, P, Ca, Mg, Na, Fe, Mn, Zn, Cu, B and Mo in Lactuca sativa under different spectral component conditions were studied by ICP -AES technology. The results showed that: (1) Single or combined spectrums corresponding to the absorbing peaks of chlorophyll a and b (450, 660 nm) could enhance the absorbing ability of roots especially for mineral elements Na, Fe, Mn, Cu and Mo, the single red spectrum had the most significant promoting effect under which contents of those four elements were respectively 7.

[Analysis of the mineral elements of Lactuca sativa under the condition of different spectral components].

Mineral elements absorption and content of Lactuca sativa under different spectral component conditions were studied by ICP-AES technology. The results showed that: (1) For Lactuca sativa, the average proportion for Ca : Mg : K : Na : P was 5.5 : 2.

[Effects of water supply tension on photosynthetic characteristics and root activity of greenhouse cucumber].

To study the effects of soil water content on the photosynthesis, fluorescence parameters, and root growth of greenhouse cucumber (Cucumis sativus L.), a pot experiment was conducted, using a negative pressure water supplying and controlling device to control soil moisture regime. Seven levels of water supply tension (WST), i.