Roots play a key role in drought-tolerance of poplars as suggested by reciprocal grafting between male and female clones

Abstract

Drought stress influences the growth of plants and thus grafting has been widely used to improve tolerance to abiotic stresses. Poplars possess sex-specific responses to drought stress, but how male or female rootstock affect the grafted plant is little known. To explore the mechanisms underlying changes in drought tolerance caused by grafting, we investigated the changes in growth, leaf traits, gas exchange and antioxidant enzyme activities of reciprocally grafted seedlings between Populus euramericana cv. "Nanlin895" (NL-895) (female) and Populus deltiodes cv."3412" (NL-3412) (male) under water deficit stress with 30% field capacity for 30 d. Results showed that drought stress affected adversely growth, morphological, and physiological characteristics in all seedlings studied. Grafted seedlings with male roots can effectively alleviated the inhibition of growth induced by drought stress, as shown by higher WUE, activities of SOD, POD and CAT, and lower levels of lipid peroxidation. Male seedlings with female roots were found to be less tolerance to drought than non-grafted male clones and female scions with male roots, but more tolerance than non-grafted female clones. This results suggested that drought tolerance of grafted seedlings is primarily caused by the rootstock, although the scion also affects the grafted plant. Thus, paying attention on the root genotype can provide an important means of improving the drought tolerance of poplars.

Effect of Cold Stress on Growth, Physiological Characteristics, and Calvin-Cycle-Related Gene Expression of Grafted Watermelon Seedlings of Different Gourd Rootstocks

“…The extraction of antioxidant enzymes and the determination of those enzyme activities (SOD, CAT, and POD) were all carried out according to our previous methods [18], while the activity of GPX was measured following Huang et al [30]. Electrophoretic separation of POD and CAT bands was performed as described by Lu et al [18] and Woodbury et al [31].…”

“…Accumulating evidence has demonstrated that certain stresses lead to oxidative stress by overproducing reactive oxygen species (ROS), such as superoxide anions (O 2 − ) and hydrogen peroxide (H 2 O 2 ). The improved performance of grafted plants, especially under abiotic stress, is usually associated with the higher accumulation of osmolytes, such as proline, as well as higher antioxidant enzyme activity, such as that of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), which protect the cellular systems from the cytotoxic damage by ROS [18,19]. Moreover, some studies have shown that grafted plants have enhanced tolerance to stress via the induced the expression of some key genes, especially those related to photosynthesis.…”

Integration of mRNA and microRNA analysis reveals the molecular mechanisms underlying drought stress tolerance in maize (Zea mays L.)

“…Drought stress severely restricts the growth and development of corn plants in the field and is among abiotic stress factors important for yield loss ( Guo et al., 2021 ). When grown under drought conditions, the roots of most plants change significantly ( Chen et al., 2020 ); therefore, topics related to the response of the maize root system to drought resistance have become the focus of intense research. In this study, the morphological and physiological differences of maize seedlings under drought stress were investigated and a series of DEMIRs and DEMRs in the maize seedling root system in response to drought were identified.…”

Grafting enhances plants drought resistance: Current understanding, mechanisms, and future perspectives

“…Since drought greatly influences plant growth and development, it is essential to learn how to mitigate the negative effects through grafting ( Zia et al., 2021 ). Grafting improves plant drought resistance ( Ellialtio­glu et al., 2019 ; Lopez-Serrano et al., 2019 ; Chen et al., 2020 ), which is primarily determined by the rootstock, despite the scion also affecting the grafted plant ( Han et al., 2013 ; Han et al., 2019 ; Chen et al., 2020 ; Lopez-Hinojosa et al., 2021 ). Despite there being multiple studies and reviews on grafting and drought resistance, few have summarized how the molecular response of grafted plants is linked to their physiology and phenotype under drought stress.…”