| The relationship between source and sink is the physiological basis of wheat high yield. It is important to elucidate the physiological effects of source-sink adjusting modes on wheat yield formation for deepening physiological and ecological theory of wheat high-yielding and guiding wheat high-yielding cultivation with different spike types. In this study, two cultivars with different spike types Su2001(large spike type) and Yumai 49(multiple spike type) were used under field test conditions. With leaf removal, floret removal and spraying fertilizers to set different source-sink regulation treatments, combined with modern physiological and biochemical technology, we comprehensively compared physiological and metabolic differences in different spike type wheat varieties and analyzed the regulation of source-sink on wheat photosynthetic characteristics, senescence response and carbon- nitrogen accumulation and transfer and the related enzyme activities. We clarified the differences of varieties about wheat ear economic character and grain quality and regulation mode effect of source sink balance. It provides theoretical basis and technical approach for deepening the theory of high yield wheat and guiding high yield cultivation mode for wheat with different spike types. The main results are as follows: 1 Source-sink regulation on photosynthetic characteristics and senescence physiology in two wheat spike typesAfter wheat heading, with the accelerated aging process, chlorophyll content, photosynthetic rate, SOD and CAT activity decreased, whereas POD activity showed a rise change after the first drop and MDA accumulation increased. Leaf removal and spraying fertilizer treatment increased the photosynthetic rate and chlorophyll content, protective enzymes SOD, CAT and POD activity increased as well, but MDA content decreased, leaf photosynthetic active duration prolonged, and senescence delayed; floret removal decreased photosynthetic rate and chlorophyll content and SOD, CAT and POD activity, but increased MDA content and promoted the process of senescence; the high value duration of photosynthetic rate in leaves changed little. The effect of source-sink regulation on leaf senescence is bigger in multi spike type cultivar than in large spike type cultivar. From above, taking appropriate management measures in late growth stages of wheat according to different spike-type cultivars to effectively regulate source-sink balance can delay leaf senescence and enhance leaf source functions. 2 Source-sink regulation on wheat carbon and nitrogen physiological metabolism in two spike typesThe source-sink regulation has significant role in the regulation of plant carbon and nitrogen metabolism. Compared with the control, the SPS activity enhanced in remaining leaves after leaf removal, and soluble sugar and sucrose content of leaves increased; NR activity, GS activity, soluble protein content increased but SS activity, soluble sugar and sucrose content and starch content in grain decreased. After floret removal, source / sink increased, SPS activity in flag leaf decreased, and the soluble sugar and sucrose content, NR activity and GS activity of leaves decreased; grain SS activity, soluble sugar content and sucrose content and starch content increased. The change of leaf physiological metabolism after spraying fertilizer is the same as leaf removal but contrary to floret removal. On the other hand, spraying fertilizer regulation effect on the physiological metabolism in grain is the same as leaf removal but contrary to floret removal.With the increase of the number of leaf removal, rising of leaf position, effect of leaf removal increases and large spike type cultivar is more intense than multi-spike cultivar. Effects of different floret removal treatments associated with panicle type. Removing all basal first flowers in spikelet has larger influence on multiple spike type cultivar, whereas removing the third or above flowers in spikelet and floret has more influence on large spike cultivar than the multi spike cultivar. Spraying fertilizer effect on carbon and nitrogen metabolism is different in spike type cultivars. Spraying nitrogen has a greater impact on the multi spike type cultivar, but effects of spraying phosphorus and potassium in large spike type cultivar is more obvious. Spraying effect of mixed nitrogen/phosphorus/potassium is better than the nitrogen or phosphorus spray alone. On the nitrogen/ phosphorus/potassium mixed spraying effect, multi spike cultivar is better than large spike type cultivar. 3 Source sink regulation on wheat carbon and nitrogen accumulation and transfer in two spike typesLeaf removal significantly increased carbon and nitrogen translocation amount and the translocation between stem and sheath and storage rate, but also improved the spike organs storage substance transportation amount and transport rate. After Leaf removal to shrink source, carbon and nitrogen storage before anthesis has a bigger contribution on grain yield and nitrogen absorption. The more removing leaf number, the higher removiong position, the greater contribution of material storage to grain yield; carbon and nitrogen accumulation amount of leaf removal treatment post anthesis decreased, its contribution to grain yield and grain nitrogen absorption reduced.Floret removal reduced carbon and nitrogen in vegetative organs translocation to grain and transport rate, but contribution of pre-anthesis stored assimilates to grain weight improved; after floret removal, amount of post-anthesis transferring to grain decreased, and its contribution to grain yield reduced; floret removal reduced storage with flowers nitrogen to grain nitrogen accumulation rate, by increasing the nitrogen pre-anthesis, then increased post-anthesis nitrogen uptake of grain nitrogen contribution rate, especially in large spike type cultivar.Spraying fertilizer increased vegetative organs storage material transport, transport rate and amount of contribution rate of pre-anthesis to grain yield. The effect of material transport by spraying is N/P/K > N > P/K. Spraying P/K increased the contribution rate of storage substances to grain yield but nitrogen has little effect. As for the matter accumulation and contribution, all spraying fertilizer treatments significantly increased post-anthesis matter accumulation. Mixed spraying nitrogen,phosphorus and potassium plays the biggest role; spraying P/K into large spike type cultivar and N into multiple spike cultivar are also significant; spraying fertilizer after anthesis decline the accumulation of material on grain yield. Thinking about the accumulation and transport of nitrogen, spraying nitrogen, phosphorus and potassium significantly increased the nitrogen storage of pre-anthesis in vegetative organs e to grain transport, transport volume and operation rate were increased, then spray of nitrogen, phosphorus and potassium and the spraying effect is not obvious, but all spraying fertilizers nitrogen storage before anthesis to grain nitrogen contribution rate decreased; spraying fertilizers significantly increased post-anthesis nitrogen accumulation and its contribution to grain nitrogen rate, the effect of regulation order jet of nitrogen phosphorus and potassium nitrogen spray P/K. 4 Effect of source-sink regulation in two spike-type wheat cultivars on grain fullness and grain weight per spikeGrain volume and fullness, 1000-grain weight and grain weight per spike of two spike-type wheat cultivars were influenced by source-sink regulation measures. After leaf removal the grain volume and fullness reduced, 1000-grain weight decreased, the setting grains decreased, grain weight per spike decreased significantly with the increase of the number of leaf removal and leaf position, the effect of leaf removal increased. Floret removal increased grain volume, improved grain plumpness and 1000-grain weight, but the setting grains per spike and grain weight per spike reduced; effect of removing the third floret and above florets obviously on the large spike-type cultivar was significant, and less influence on multi spike type cultivar; effect of removing the base first floret of all spikelets on multiple spike type varieties was significantly. Spraying fertilizer increased grain volume and fullness, increased the setting grain number and 1000 grain weight increased, in the meantime the grain weight per spike increased significantly; mixed spraying nitrogen, phosphorus and potassium was the most effective, only spraying nitrogen was a greater impact on the multi spike-type cultivar, spray of phosphorus and potassium in large spike type cultivar was effective. 5 Effect of Source-sink regulation on grain quality characters in high-yield wheat with two spike type cultivarsLeaf removal reduced the content of grain protein, single grain protein accumulation amount, the content of globulin and gliadin content, increased the content of albumin and glutelin content, glutenin/gliadin increased, reducing the wet gluten content, gluten index and sedimentation volue increased, filling number is stable. Effects of leaf removal on grain starch and pentosan were that,starch content and starch accumulation in single particle decreased, single stem starch yield decreased, amylose, amylopectin and amylose / amylopectin declined, increasing the total pentosan content, decrease of water soluble pentosan content. With the increase of leaf removal and leaf position increased, the effect of regulation related quality index increase, effect of leaf removal to the multi spike cultivars is more obvious than that of large spike type cultivar.Floret removal increased the content of grain protein and single grain protein accumulation, single stem protein yield declined, decreased the content of glutenin and albumin, globulin and gliadin content increased, glutenin/gliadin decreased, increased wet gluten content, gluten index and sedimentation value decreased, filling number increased less. After floret removal single grain starch accumulation increased significantly, single stem starch yield decreased, increased amylose, amylopectin content and amylose/amylopectin increased, reducing the total pentosan content, increased the content of water soluble pentosan. For the multi spike cultivar the effect of removing the basal first floret in all spikelets on quality characters was larger, removing the third floret and above florets has little effect on the grain quality of the multi spike cultivar, and large spike type cultivar contrary.Spraying fertilizers increased the content of grain protein, single grain protein accumulation and single stem protein yield, but the content of albumin and globulin decreased, gliadin content and glutenin content increased protein, glutenin / gliadin increased, increased wet gluten content, gluten index and sedimentation value increased. Spraying fertilizers increased the starch content, single grain starch accumulation and single stem starch yield, reduced the content of amylose, amylopectin content increased, reduced amylose/amylopectin, reduced the total pentosan content, water-soluble pentosan content increased, reduced the content of the water-insoluble pentosan.Comparison of the effects of different spraying fertilizers,the effect of the mixed spraying nitrogen,phosphorus and potassium on starch content on single grain starch accumulation and starch yield was more significant. Considering of the protein content and flour quality, spraying nitrogen is especially suitable for the multi spike type cultivar, considering of collaborative improvement on grain yield and quality, mixed spraying nitrogen, phosphorus and potassium is more suitable for two spike type cultivars. |
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