Reproducitve Ecology Characteristics Of Tamarix Chinensis And Apocynum Venetum

Tamarix chinensis is an important constructive species in arid and semi-arid areas. Thestudy on characteristics of reproductive ecology will be conductive to its effective use andcultivation. In order to understand the reproductive biology of Tamarix chinensis andApocynum venetum, we conducted a field investigation about the flowering dynamics, pollenviability, stigma receptivity, floral visitors and their behaviors, pollen ovule rate (P/O),outcrossing index(OCI), rate of fruitset of T. chinensis and A. venetum in the middle reachesof Heihe River and Yantai seashore areas. The main results were as follows:（1）Stigma receptivity and the flowering period of the two areas of T. chinensis aresimilar. The flowering of inflorescence were2—5days. In the flowering day, stigmareceptivity of two areas of T. chinensis were the peaking, after4days, the stigma receptivityreduces to0. The flowering of A. venetum were4—6days, the community flowering season isJune to August, Stigma receptivity of A. venetum achieve the maximum at2days later inflowering, the Stigma receptivity can last for4days.（2）The pollen viability, floral visitors and their behaviors of the two areas of T.chinensis are greatly different. In the first flowering day, the pollen viability of T. chinensis inthe middle reaches of Heihe river is as high as62±4.31%or more, and the peak is82.12±7.23%, after4days, the pollen viability reduced to0. In the first flowering day, thehighest pollen viability of T. chinensis in the seashore of Yantai is89.13±7.23%, after4days,the pollen viability decreased to11±1.12%. In the flowering day, the pollen viability of A.venetum achieve the maximum at3hours later, after4days, the pollen viability reduce to0,（3）The most common floral visitors of two species were arranged in Orderhymenoptera, of which Bembix melanura Morawitz, Megachile (Amegachile) kagianaCockerell, Megachila (Eutricharaea) abluta Cockerell, Episyrphus balteatus Degeer,Pieris rapae Linnaeus, were the effective pollinators of T. chinensis in the middle reaches ofHeihe river. Ichneumon sp, Metasyrphus corollae, Delia platura were the main pollinators ofT. chinensis in the seashore of Yantai. More than10species of insects were observed to visitthe flowering of A. venetum. The most common floral visitors were arranged in Hymenoptera,of which Ichneumon, Megachile (Amegachile) kagiana Cockerell, Apis melliferaligusticaSpinola, Apis melliferaligustica Spinola, Episyrphus balteatus Degeer, Pieris rapae Linnaeus were the effective pollinators.（4）The difference of P/O, OCI, and the fruitset rate is not significant.The pollen ovulerate of two areas of T. chinensis is373.6±71.9,382.1±86.2; the highest rate of fruit is89.72±7.76%,93.17±8.21%; the OCI is3. The results indicated that outcross is the main formin breeding system of the two areas of T. chinensis. The pollen ovule rate of A. venetum was36.2, the outcrossing index (OCI) was2, Fruit set rate of two groups of A. venetum were2.79±0.99%and3.41±1.05%, The results indicated that selfing is the main form in breedingsystem of A. venetum. The Fruit set rate is low. In the process of pollination, the floralvisiting insects play a positive role in promoting the Fruit set rate.