Physiological Mechanism Of Tiller And Spike Development In "Multi-spike Coordination Type" Wheat In Southwest China

Southwest wheat of China is one of China's major wheat producing area,but due to the special ecological environment,the "ecological spike capacity" limits the wheat yield further improved."Multi-spike coordination type" wheat series interpreted as maintaining the larger panicle meanwhile increase more ear number,it can coordinate the relationship kernel weight with Spike number,has a positive role to break away the "ecological spike capacity" from Southwest wheat of China.A series of new cultivars with "Multi-spike coordination type" are famous for their high yield protential and tillers proportion,and those new cultivars are popularized higher and higher.Considering the special climate in the province of Southwest wheat of China,these new type will make great contribution to achieving high tillers and high yield in Southwest China.In this study,three wheat-types of Multi-spike coordination type,Large spike and Intermediate-type were investigated on whole growth/development period,involving traits:morphological and physiological characteristics on the roots,all the primordiums and leaf changes of main stems and tillers,and some single plant physiological changes,endogenous hormones on main stem and tillers,four the antioxidant enzymes and soluble sugar,photosynthetic and filling rates,and so on.More manifests "Multi-spike coordination type" wheat of productive panicles per plant characteristics on Sichuan province,provide research basis for wheat breeding in Southwest wheat of China.The results are obtained as follows:1.The analysis on appearing of tillers and changes of leaf-age and effects on earing,the differences on leaf-age remainders of main stem and all tillers are not significant for all primary tillers in the three type wheat.Leaf-age remainder on secondary tillers of"Multi-spike coordination type" wheat(3.713)is the smallest;tiller emergence time(7.41 days)and adjacent tiller's time interval(2.66 days)is the shortest;the adjacent apex primordium of primary tiller growth deviation is on 0.98-1.10 stages;Fibonacci sequence model show that the average time for emergence of tillers is the least,under the same leaf age,average growth stage of tillers' primordium is the highest.Leaf-age remainders in Large spike type and Intermediate type on main stem and secondary tiller(large spike type wheat 5.328,Intermediate type wheat 4.113)becomes larger;average time for tiller appearing(8.53,8.36 days)and adjacent tiller's time intervals(days 4.23 and 3.33)are longer;tiller primordium adjacent growth deviation(Large spike type 1.25-1.87,Intermediate type 1.18-1.44)get longer;Fibonacci sequence model show that,tillers appear for a longer time,under the same leaf age,average growth stage of tiller primordium is lower.Tiller appearing and growing of "Multi-spike coordination type" is uniform,leaf remainders on main stem and tillers are the minimum,Percentages of Productive Tiller(87.50%)and yield(4752.6 kg.ha-1)is the highest.2.Analysis on the relation between percentages of productive tiller and roots differences in three type wheat.Average secondary Roots number(51.84),Root length(9.32 cm),Root Respiration rate(5.53 mg.g-1h-1),Root volume(5.63 cm3),Root dry weight(0.674g,Root shoot ratio(0.131),and Root activity per plant(22.21 ug.g-1 FW.h-1)per plant in'Multi-spike coordination type' are the highest.The primary Root length(17.72cm),primary Root respiratory rate(8.17 mg.g-1h-1),Soluble sugar in root(21.58 mg.g-1)in Large spike are the highest,and the difference was significant.Root dry weight,Root soluble sugar and Root activity of Jointing stage determines the eventually the tiller panicle size,Root dry weight,Soluble sugar in roots is higher,higher in Root activity,and ultimately percentages of productive tiller is higher.3.Effects of different the endogenous hormone levels in main stem and tillers on percentages of productive tiller,"Multi-spike coordination type" of difference between adjacent two tillers hormone levels GAs(0.59 ng.g-1FW),IAA(1.01 ng.g-1FW),ZR(0.129 ng.g-1FW),ABA(8.726 ng.g-1FW)were the minimum on average,secondary tillers IAA/ABA(0.65)and ZR/ABA(0.08)are characterized by the highest,IAA/ZR + Z was the lowest(1.06);Large spike type and Intermediate-type of endogenous hormone content are characterized by obvious heterogeneous change,average difference between adjacent tillers per plant performance are different,Large spike type in GAs(0.845 ng.g-1FW),IAA(2.21 ng.g-1FW),ZR(0.275 ng.g-1FW),ABA(11.231 ng.g-1FW),Intermediate type in GAs(0.845 ng.g-1FW),IAA(1.865 ng.g-1FW),ZR(0.209 ng.g-1FW),ABA(19.758 ng.g-1FW),two types of wheat secondary tillers of IAA/ABA(0.33,0.33)and ZR/ABA ratio(0.03,0.16)are characterized by lower,IAA/ZR + Z(1.47,1.21)are characterized by higher.Every tiller of "Multi-spike coordination type"wheat in GA3,IAA,ZR content ratios are uniform and orderly change with tiller position increased,GA3,IAA,ZR content of per plant tiller are the highest,ABA is the minimum,final ensure on earing for the epigenetic tillers.4.Influence of Antioxidant Reductase level in main stem and tillers on tiller earing.Average difference on young ear or stem apex primordium adjacent tillers in"Multi-spike coordination type"of SOD(20.39 vg-l.min-1FW),POD(18.63 vg-1.min-1FW),CAT(111.9 vg-1.min-1FW),SP(1.76 mg.g-1FW)and MDA(0.362 umol.g-1FM)minimum.Adjacent tiller content difference per plant in Large spike type and Intermediate-type wheat of SOD(56.09,44.45 vg-1.min-1FW)and POD(4.541,42.42vg-l.min-1FW),CAT(1.578 1.431 vg-l.min-1FW)and SP(3.576,3.158 mg.g-1FW)and MDA(0.385,0.415umol.g-1FM)is increased,the tiller senescence to death has a certain role in promoting.Young ear or tiller apex primordium in "Multi-spike coordination type"of SOD,POD,CAT,SP and MDA content,decrease evenly or even increasing trend with elevating tiller position,the average concentration of four Antioxidant Reductase are the highest,and MDA content was the minimum.5.The relation between panicle traits and yield of tillers,adjacent tiller mean difference value in"Multi-spike coordination type" wheat of mean grain number per spike(1.69),pregnant spikelet number(1.61),average grain weight(2.31),tiller infertility spikelet number(0.87)are the minimum,and percentage of earbearing tiller(87.50%)and yield(4752.6 Ha-1)is the highest.Adjacent tillers mean difference in Large spike type and Intermediate-type wheat of the grain number per spike,the number of pregnant spikelet number,grain weight and spikelet sterility(4.72,1.87),(3.41,2.47),(4.24mg,2.75mg),(1.68,1.52)get larger,percentage of earbearing tiller(72.57%,62.78%)and yield(3968.8 kg.ha-1,3273.4 kg.ha-1)got lower respectively.The yield characters of tiller per plant in the"Multi-spike coordination type" wheat are increasing with tillers' order,the highest grain weight(23.75g)was highest,and the yield was highest.Tillers per plant in "Multi-spike coordination type" wheat average spike number,grain number per spike,fertile spikelet number,grain weight of single ear are orderly reduced with the increase of tillers,panicles infertility is in a homogeneously order too.6.Photosynthetic rate effect on yield for function leaves on main stem and of top leaf on tillers,the top third leaf from top fifth leaf of "Multi-spike coordination type" wheat in photosynthetic rate was highest(17.7-3.45 umolCO2M-2S-1);an average difference photosynthetic rate of adjacent tiller parietal of 1.51-1.82 umolCO2M-2S-1;average photosynthetic rate per tiller of single plant was the highest(16.17 umolCO2M-2S-1).The photosynthetic rate of flag leaf(31.67 umolCO2M-2S-1)and top second leaf(26.63 umolCO2M-2S-1)in Large spike wheat was the strongest.photosynthetic rate deviation on adjacent to tiller parietal in Large spike type and Intermediate type wheat between 1.76 umolCO2M-2S-1 and 1.57 umolCO2M-2S-1;average photosynthetic rate per tiller of single plant(Large spike type wheat 12.29 umolCO2M-2S-1,Intermediate type wheat 12.05 umolCO2M-2S-1)decreased."Multi-spike coordination type" wheat is evenly parietal distributions on top leaves photosynthetic rate of tiller and main stem.7.The analysis of difference in grain filling process and in grain filling rate per plant in three type wheat,from flowering to grain filling,canopy temperature is increasing.Canopy average temperature was the lowest(19.34?)in "Multi-spike coordination type" wheat,Grain filling peak(2.015 mg.kernel.d-1)reached the highest at 16 days after anthesis;the grain filling rate difference vaule of adjacent tiller is 0.121-0.165 mg.kernel,d-1 on average.The highest grain filling rate(1.014.mg.kernal.d-1)in Large spike type wheat,canopy temperature in filling stage(22.72?)is the minimum;Grain filling peak(1.963 mg.kernal.d-1)reached the highest at 21 days after anthesis;grain filling peak is later about 5 days compared with the other two types of wheat;average grain filling rate difference vaule of adjacent tillers(Large spike type 0.195-0.224 mg.kernal.d-1,Intermediate-type wheat 0.145-0.167 mg.kernal.d-1)becomes larger.The grain filling rate of tiller per plant of wheat was decreased at a constant speed with the increase of tiller in"Multi-spike coordination type" wheat,and the average grain filling rate was highest,so the yield was highest.8.Conclusion:"Multi-spike coordination type" wheat is best.Appeared time for tillering more evenly,the apex primordium of tillers has a uniform downward trend with increasing of tiller,leaf remainders on main stem and tillers are the minimum;coincide with Fibonacci sequence model;better in root traits,distribution of endogenous hormones and antioxidative reductase level in main stems and tillers are evenly decreased distribution trend,earbearing tiller percentage is higher and panicle number per plant is more.With the tiller increasing,the photosynthetic rate and grain filling rate were decreased well-distributed,ear characters were the best,percentage of effective tillers and yield are the highest.