Rolls Of Heavy Metals On Pollen Tube Growth Of Pear

In order to study the properties of the effect and mechanism of several common heavy metals on pear pollen tube growth.The study detected the effects of Cd,Cu,Pb,Ni and Zn treatments on‘Huanghua'and‘Cuiguan'pear pollen germination and tube growth with the vitality,the shape of pollen tube tip,the ROS on the tube tip,the respiratory intensity and the cytoskeleton on the growth,respectively.The main results as follows:1.25,50 or 100?mol L^-11 Ni²⁺,Cd²⁺,Cu²⁺,Pb²⁺and Zn²⁺showed inhibition of‘Huanghua'and‘Cuiguan'pear pollen germination rate and tube growth.The inhibition degree was along with the concentration increase of the above heavy metal.Among these heavy metals,Pb²⁺treatment showed the least effects on pollen germination rate and tube growth,while Cu²⁺treatment showed the highest.Furthermore,varying degrees of swollen tip and sub-tip could be observed in pear pollen tube after different heavy metal treatments.The swollen tip and sub-tip tube rate was the lowest after Pb treatment,whereas Cu²⁺treatment showed the highest effect,the swelling rate was significant?P<0.05?higher than other treatments except 100?mol L^-1 Zn²⁺treatment on‘Cuiguan'pear pollen tube.2.Under the test concentration,which five kinds of heavy metals on‘Huanghua'and‘Cuiguan'pear pollen tube length of the average performance is consistent,both average length of pear pollen tube showed inhibitory effect,the more obvious with the increase of concentration of heavy metals.After removing heavy metal ions from the medium,the speed of pollen tube elongation was improved,but after the pollen tubecontinue to grow until 24 hours,it could be found the pollen tube stops elongating indicates that the damage in pollen tube was irreversible.The higher the degree of swelling on the tip of the pollen tube,the lower the extension ratio and length of the tube after recovery,while there was no correlation between the presence or absence of vacuoles in the pollen tube and the degree of swelling.3.The heavy metal treatment tested in the work had a weakening effect on the vitality and respiratory intensity of the pollen tube of‘Huanghua'and‘Cuiguan'pear pollen tube,and the higher the concentration of heavy metals,the more serious the weakening.The vitality and respiratory intensity of two kinds of pear pollen tubes were greatest inhibitory effect with Cu²⁺,while Pb²⁺showed the least.Furthermore,pollen tube tip-localized ROS was disrupted by heavy metals treatments(100?mol L^-1 Ni²⁺,Cd²⁺,Pb²⁺,Zn²⁺and 25?mol L^-1 Cu²⁺)in present study.Both the‘Huanghua'and‘Cuiguan'pear pollen tube distributed rich microfilament cytoskeleton,and microfilament cytoskeleton appeared different degree of depolymerization after the heavy metal(100?mol L^-1 Ni²⁺,Cd²⁺,Pb²⁺,Zn²⁺and Cu²⁺)treatment,especially Cu²⁺.