| The mechanism of rice production increase by the formulated fertilizer synergist, manufactured by the Key Laboratory of Phytohormones of Hunan Agricultural University, was studied with three years of the plot experiment, pot experiment and demonstration experimental areas as well as laboratory analysis determination in the paper. The main conclusions are as follows:1. The results show that growth, the total volume, total absorption area and active absorption area of rice root system are significantly promoted with application of synergist to formulated fertilizers at standard of 0.01. Root activities, however, are little affected. Synergist has some effects on photosynthetic characteristics of lower leaves, and can enhance the content of chlorophyll slightly and increase the photosynthetic rate of rice. Synergist can raise the conductance to H2O and the transpiration rate as well, improve the inner condition of nutrient transportation and increase the absorption power of rice root system. Synergist can also increase tillering capability and dry weight accumulation in rice plant. Significant differences in root characteristics, dry weight accumulation and economic characteristics are also found between with and without fertilizer application at standard of 0.01.2. The levels of endogenous phytohormones in rice vary a lot under the conditions of soil progressing drought. At the beginning of drought, the contents of IAA both in root and leaves decrease, however, the contents of ZR and GA3 in root decrease but increase in leaves. The contents of ABA in root and leaves raise greatly, They are even as high as 58 to 101 times in root. The contents of IAA and ABA increase with the increase of soil drought, this phenomenon indicates that rice plant has an adaptive process to drought. Synergist added to rice special formulated fertilizers can promote the accumulation of ABA and slow down proline accumulation in plants so as to increase the capability of stress resistance in rice. As a result, the synthetic capability of ABA should be an index to stress resistance, the accumulation of proline, however, is the consequence of stress harm to rice plants.3. The values of stomatic limitation (Ls) of synergist treatment c still tend to be up after 11 days drought, however the Ls of CK decrease to 0.09, and Ls of synergist treatment b also have a descending trend. This illustrates that the photosynthetic capacity of the mesophyllous cells in CK plants has been serious damaged. The degree of photosynthetic inhibition in plants with the synergist treatment b is lower than that of CK, the reason ofphotosynthetic inhibition in plants with synergist treatment c is still due to stomatic limitation. It is suggested that the synergist can lighten the degree of photosynthetic capacity in the paddy plants under the soil progressing drought, and the effects of the treatment of 20% application reduce is better than others.4. The net photosynthetic rate of every treatment decrease gradually with the soil progressing drought. The net photosynthetic rate of CK is same as that of the synergist treatment b and the net photosynthetic rate of synergist treatment c is slightly lower than it before drought. But after 7 days soil progressing drought, the net photosynthetic rate of CK is no more than one half of the synergist treatments. The value of CK is 2.6mol CO2 m-2s-1,the highest value of synergist treatment b is 6.8 mol CO2 m-2s-1,and the value of treatment c is 5.2 mol CO2 m-1.The photosynthesis of CK is very low after 11 days soil progressing drought and its net photosynthetic rate is only 0.8u mol CO2 m-2S-1, the net photosynthetic rate of synergist treatment b is 1.6mol CO2 -2S-1, however the synergist treatment c still has a high value of 5.1 mol CO2 m-2.The result indicates that the synergist can lighten the extent of photosynthesis inhibition under the stress of soil progressing drought.5. The conductance to H2O and the transpiration rate in plants with the synergist treatments are higher than that of...
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