Study On Regulation Of Exogenous Polyamines On Self-pollinated Fruiting In Yali Pear

The Yali Pear is our country's famous and original pear variety and also is one kind of host fruit trees in Hebei. It is at the first place on production or planting area and creating the huge economic value. But pear belongs to the kind of gametophytic self-incompatibility, the percentage of self-pollinated fruit set id extremely low, so it's necessary to arrange varieties for pollination or perform artificial pollination for completing pollination an fertilization in field. Although these, the cut of production often happen because of the pollinated tree disposition the artificial pollination untimely and improper climatic condition in the period of flowering. On the other hand, pear which xenin phenomenon is obvious, if the pollinated tree id matched improperly, will suffer the lose of the typical characters, the outcome of producing abnormal fruit, rough surface of fruit and poor edible quality, which make the appearance and the intrinsic quality drop off and affect seriously the production and economic enhancement in pear. The polyamines are a kind of low molecular fatty group nitrogenous base. They have a close relationship with the synthesis, the organ differentiation, the membrane stability and the endogenous hormone balance. They were reported to have various effects on germination, blossoming, fruit set, differentiation of flower bud, sex expression, fruit growth, root system formation and resistance. Therefore to study the intrinsic relationship between polyamines and the self-incompatibility of pear is quite important;however, there has been little study done on the facet that the polyamines could regulate the self-incompatibility of pear. In this paper, the effects of exogenous polyamines and their synthetic inhibitor MGBG on pollination and fertilization and endogenous polyamines> hormones and polyamine oxidase during the period of fruit growing were studied with the Yali pear. The main results are as follows:1. By joining the different concentrations exogenous polyamines and its synthesis inhibitor MGBG in the liquid media, the situation of pollen germination was examined, result showed that effects of polyamines on pollen germination of Yali pear varied from the kind and concentration of polyamines. Among: Put at 0.25mmol/L significantly prompted pollen germination, while rising to 1.00 mmol/L it caused pollen germination significantly to decrease;0.25 mmol/L Spd significantly prompted pollen germination, but other concentrations did not have the obvious effect;Spm at 0.005 mmol/L and 0.05 mmol/L promoted pollen germination obviously, but at 0.05 mmol/L theeffect is the most significant;Polyamines synthesis inhibitor MGBG then made the pollen germination to suffer suppression, and also the level of inhibitory action strengthened along with the MGBG concentration increased.2. By examining the ovule longevity under fluorescence microscope, three kinds of polyamines treatment delayed the ovule senescence. Among: Put at three concentrations all obviously delayed the ovule senescence, when at 0.25 mmol/L the effect is the most significant;Spd at 0.01 mmol/L had the best effect, although other concentrations had similar function of delaying ovule senescence obviously, the effect reduced along with the concentration increased;The effect of 0.05 mmol/L Spm is the most significant, the effect of other concentration which is higher than or is lower than this concentration reduced, but the ovule longevity still significantly was higher than the control;MGBG similarly enabled the ovule longevity to lengthen, but the effect is inferior to three kinds of polyamines.3. In the field the effects of different concentrations exogenous polyamines on the percentage of self-pollinated fruit set in Yali pear varied from the kind and concentration of polyamines. Combined the results of two years continuously, it is found that three kinds of concentrations Put treatment and Spd treatment significantly prompted the percentage of self-pollinated fruit set in Yali pear, and they had the most obvious effect at 0.25 mmol/L;Spm also made the percentage of self-pollinated fruit set significantly to increase similarly under various concentrations, but the effect reduced along with the concentration to elevate, when the concentration is 0.005 mmol/L the effect is the most significant. Take the best concentration of three kinds of polyamines to carry on the comparison, the order of the percentage of self-pollinated fruit set is in turn: Put (0.25 mmol/L) >Spm (0.005 mmol/L) >Spd (0.25 mmol/L). MGBG then made the percentage of self-pollinated fruit set to suffer obvious suppression, and the percentage of self-pollinated fruit set reduced along with the MGBG concentration increased.4. By spraying the different concentrations exogenous polyamines in the period of full flowering and determining the content of endogenous polyamines in fruit of self-pollinated Yali pear, it is found that the effects of exogenous polyamines on the content of endogenous polyamines of Yali pear varied from the kind and concentration of potyamines. Among: In different concentrations exogenous Put, the content of 0.25 mmol/L Put is higher than other two concentrations, and significantly is higher than the control;In three kindS of concentrations Spd processing, content of endogenous polyamines similarly of 0.25 mmol/L Spd is highest, significantly is higher than the control;In different concentrations exogenous Spm, 0.005 mmol/L is highest, and significantly is higher than the control. Adds up to the content of endogenous polyamines in fruit of self-pollinated Yali pear of three kinds of exogenous polyamines, the result is: Put (0.25 mmol/L) >Spd (0.25 mmol/L) >Spm (0.005 mmol/L). But MGBG made endogenous polyamines content obviously to reduce, significantly is lower than the control.5. By determination on the content of hormones in fruit of Yali pear during a week after flowered to fruit dropping in June, it is found the exogenous polyamines significantly increasedthe endogenous value of (1AA+GA3+ZR)/ABA in the fruit. In three kinds of concentrations Put treatment, 0.25 mmol/LPut increased the value most significantly, although other concentrations caused the endogenous value of (IAA+GA3+ZR)/ABA significantly to be higher than the ccontrol similarly, the effect is inferior to 0.25 mmol/LPut;Three different concentrations Spd similarly caused the endogenous value of (IAA+GA3+ZR)/AB in self-pollinated fruit obviously to be higher than the control, but the effect of 1.00 mmol/LSpd is the most significant;The Spm caused the endogenous value of (IAA+GA3+ZR)/ABA obviously to be higher than the control in the majority of times, 0.005 mmol/LSpm is best. Chooses the concentration of highest fruit set from each kind of treatment, compares with their endogenous value of (IAA+GA3+ZR)/ABA in the fruit, the result is: Put (0.25 mmol/L) >Spd (0.25 mmol/L) >Spm (0.005 mmol/L). MGBG caused the endogenous value of (IAA+GA3+ZR)/ABA to be higher than the control except individual time, the value are lower than the control obviously other times.6. By determination on the PAO activity in fruit of self-pollinated Yali pear, it is found that the PAO activity of control had maintained the fast-growing trend continuously in the entire determination time, but the different concentration exogenous polyamines and its synthesis inhibitor MGBG significantly reduced the PAO activity in the majority of time. In different concentration Put, Spd, Spm and in MGBG treatment, respectively 0.25 mmol/L Put,0.01 mmol/L Spd, 0.05 mmol/L Spm and 0.01 mmol/L MGBG is lowest. Selects the concentration of highest fruit set from each kind of treatment, compares with their PAO activity, the order is: Put (0.25 mmol/L)