Effects Of Salinity Stress On Wheat Grain Yield And Quality Formation

The experiments were carried out at the experiment field of Jiangsu Provincial Key Lab of Crop Genetics and Physiology, Yang Zhou University, from 2004 to 2006, to study the response of plant growth and yield formation to salt stress, and the effects of salt stress on grain quality formation and physiological characteristics in wheat. The main results were as follows.1. Effects of salt stress on plant growth and yield formationThe results showed that under the condition of salt stress, plant height, the number and the earing percentage of tillers, spikes per plant, photosynthetic area, and dry matter accumulation amount, especially dry matter accumulation amount after anthesis decreased, grain number per spike and grain weight declined which resulted in the decrease of grain yield. There was no significant difference in the parameters above between low salt content treatments and control, but significant difference was found between high salt content treatments and control. Under the condition of salt stress, grain yield loss resulted from the decrease of all yield components, but mainly from the decrease of spike number.2. Effects of salt stress on grain qualityThe results indicated that under different soil salinity condition, grain protein and its component contents increased. The increase of grain protein content was mainly caused by the rising of gliadin and glutenin contents.With the increase of soil salt content, grain protein yield decreased. There was no significant difference in grain protein yield between low salt levels and control, but significant difference was found between high salt levels and control. The decline of grain protein yield mainly resulted from the decrease of grain yield. High soil salt content treatments could cause the significant drop of grain starch and its component contents.There was no significant difference in grain volume between low soil salt content treatment and control,but significant difference was found between high soil salt treatments and control. Under the condition of salt stress, grain filling rate reduced and grains shrinked.3. Effects of salt stress on grain Physiological characteristicsRoot activity and the activities of superoxide dismatase(SOD) and catalase(CAT) in flag leaves decreased with the increase of soil salinity content, while MDA content in flag leaves increased, which resulted in the early senescence of leaves and the decrease of dry matter production after anthesis, therefore, grain yield declined.