Effects Of Drought Stress On Physiological Characteristics, Pod Yield And Seed Quality Of Different Peanut Cultivars

In order to study the effects of drought stress at different growth stages on physiologicalcharacteristics, pod yield and quality of peanut, the experiment was conducted through pillarculture with rain-proof shelter with drought light-resistant peanut Luhua11and droughtresistant peanut Nongda818from2010to2011in the experimental station of ShandongAgricultural University. The results were as follows.1. The effects of drought stress at different growth stages on yield of peanutUnder the experimental condition, the pod yield and kernel yield of the two species weredecreased remarkably. The peanut was most sensitive to drought stress at the pod settingstage, followed by pegging stage and pod filling stage. At seedling stage the reduction ofoutput was the minimum. Under contrast condition, the pod yield and kernel yield ofLuhua11was higher than Nongda818, whereas lower under the condition of drought stress atdifferent growth stages, indicating that Nongda818was more drought-tolerant than Luhua11.2. The effects of drought stress at different growth stages on physiological characteristics ofpeanutDrought stress decreased the main stem height, branch length and dry weight of the twospecies. In addition, the inhibition of drought stress on vegetative growth was higher in theearly stage than the later stage. The drought stress at different growth state reduced the Pn ofthe leaves, FV/FM, ФPSⅡ, the content of Chlorophyll and Soluble protein and NR, whereasincreased the activity of superoxide dismutase(SOD), the content of proline andmalondialdeyde(MDA). Luhua11was sensitive to drought stress compared with Nongda818.Drought stress increased the root length, root to shoot ratio, root dry mass, root surfacearea, root tips, total absorption area (TAAR) and active absorption area (AAAR), but reducedthe root diameter and root vigour compared with the check. At different growth stages, themagnitude of increase or decrease of the physiological indicators were various, the result waspod setting stage>pegging stage> pod filling stage> seedling stage. The result suggests that in pod setting stage, peanut was most sensitive to drought stress, and followed by the peggingstage, whereas in the seedling stage and pod filling stage was less sensitive to drought stress.Under the condition of drought stress, Nongda818had higher root length, root to shoot ratio,root dry mass, root surface area, root tips, TAAR, AAAR and root vigour compared withLuhua11, indicating that the root growth of Nongda818is more reasonable than Luhua11.3. The effects of rewatering of different growth stages on physiological characteristics ofpeanutThe drought stress of different growth stages of peanut decreased the Pn, FV/FM, andchlorophyll content, ФPSⅡ, which increased rapidly after rewatering. Three days afterrewatering, the above physiological index had restored to a higher level, and continued toincrease at the next two days. Seven days after rewatering, the index was close to or exceededCK level. The result demonstrated that different growth stages of peanut have the significantability to recover, and the ability of Nongda818is stronger compared with Luhua11.4. The effects of drought stress at different growth stages on kernel quality of peanutAll drought treatment led to the increase of the content of soluble sugar, protein andlinoleic acid, whereas the content of fatty acid, stearic acid and oleic acid was decreased. Incontrast with Luhua11, the content of arachidic acid and palmitic acid in Nongda818wasincreased and decreased respectively under the condition of drought at the different growthstages. Under the experimental condition, the O/L of the two species was significantlyreduced. Compared with different growth stages, the induction magnitude expressed as podsetting stage>pegging stage>pod filling stage>seedling stage. However, the differencebetween varieties was not significant.