The distribution of the Critically Endangered tree Magnolia longipedunculata, is only restricted to the Nankunshan Nature Reserve in South China. The species is threatened with extinction because of its small number of individuals and the impediments to its reproduction (a combination of protogyny, a short period of stigma receptivity, and the lack of efficient pollinators). To reduce the risk of extinction, Dr. Ren Hai and his colleagues conducted two conservation translocation trials by using emerged and grafted seedlings: one is in its natural distribution location Nankunshan to augment the sole extant population, and the other is in Tianxin which is about 202 km north of Nankunshanand with very similar habitat. The trial in Tianxin was a conservation introduction with aiming to increase the number of populations and to buffer against the effects of climate change. At both sites, one ha experimental field was divided into three blocks. Each block contained two 50X30m plots, one with emerged seedlings and the other with grafted seedlings. Plants were separated by 2 m within rows and by 3 m between rows. 33 or 34 emerged seedlings or grafted seedlings in each plot at Nankunshan, and 15 in each plot at Tianxin. The regular monitoring was conducted at both sites. They found that the survival rate and growth of grafted seedlings were higher than emerged seedlings at both sites. Both the grafted seedlings and the emerged seedlings grew faster at Nankunshan than at Tianxin. Eco-physiological data indicated that grafted seedlings at both sites were as efficient or more so in light and water usage than wild individuals, whereas emerged seedlings were less efficient. Maximum photosynthetic rates and water-use efficiencies were higher for grafted seedlings and wild mature trees than for emerged seedlings but did not differ significantly between grafted seedlings and wild mature trees. Grafted seedlings flower earlier than emerged seedlings.
Thursday, November 19, 2015