Effects of Rhizome Integration on the Water Physiology of Phyllostachys edulis Clones Under Heterogeneous Water Stress

Abstract

Water is crucial to plant growth and development. Under heterogeneous environmental water deficiency, physiological integration of the rhizomatous clonal plant triggers a series of physiological cascades, which induces both signaling and physiological responses. It is known that the rhizome of Phyllostachys edulis, which connects associated clonal ramets, has important significance in this physiological integration. This significance is attributed to the sharing of water and nutrients in the vascular bundle of clonal ramets under heterogeneous water conditions. However, the physiological characteristics of physiological integration under heterogeneous water stress remain unclear. To investigate these physiological characteristics, particularly second messenger Ca 2+ signaling characteristics, long-distance hormone signaling molecules, antioxidant enzyme activity, osmotic adjustment substance, and nitrogen metabolism, ramets with a connected (where integration was allowed to take place) and severed rhizome (with no integration) were compared in this study. The vascular bundle structure of the rhizome was also observed using laser confocal microscopy. Overall, the results suggest that interconnected rhizome of P. edulis can enhance its physiological function in response to drought-induced stress under heterogeneous water deficiency. These measured changes in physiological indices serve to improve the clonal ramets' drought adaptivity through the interconnected rhizome.

Physiological integration between Bermudagrass ramets improves overall salt resistance under heterogeneous salt stress

“…The excess H 2 O 2 produced in salt response was decomposed into O 2 and H 2 O under the catalysis of CAT and POD (Schuller et al, 1996). Physiological integration significantly contributed to the decrease in MDA and H 2 O 2 contents in salt‐stressed ramets, which was in agreement with previous studies (Jing et al, 2020; Wei et al, 2019). Jing et al (2020) indicated that physiological integration improved the ability of ROS scavenging by changing of metabolism of CAT and POD, which were weaker in water‐stressed ramet and stronger in normally watered ramet.…”

“…Physiological integration significantly contributed to the decrease in MDA and H 2 O 2 contents in salt‐stressed ramets, which was in agreement with previous studies (Jing et al, 2020; Wei et al, 2019). Jing et al (2020) indicated that physiological integration improved the ability of ROS scavenging by changing of metabolism of CAT and POD, which were weaker in water‐stressed ramet and stronger in normally watered ramet. Differently, we measured equal induction of POD and CAT (including the enzymes activity and the expression of their encoding genes) in stolon connected and severed regimes.…”

“…Longitudinal long‐distance signal transduction, such as Ca 2+ and ROS, has been involved in salt response and activation of the SOS pathway (Sun et al, 2010; Tomar et al, 2021). It has been proved that Ca 2+ , as a second messenger, participated in rhizome‐mediated physiological integration of Phyllostachys sedulis under heterogeneous water deficiency (Jing et al, 2020). It needs to be further researched whether second messengers like Ca 2+ are involved in the upregulation of SOS genes mediated by physiological integration.…”

Shade Avoidance and Light Foraging of a Clonal Woody Species, Pachysandra terminalis

“…Clonal plants produce their offspring via not only sexual reproduction but also asexual reproduction, in which new individual clones with an identical gene set, called ramets, are generated [ 1 , 2 , 3 , 4 , 5 , 6 ]. Elucidating the mechanism by which clones forage resources in heterogeneous environments is a central issue in clonal plant ecology [ 4 , 5 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 ], plant growth modeling [ 23 ], and their application in vegetation management [ 17 , 18 , 19 , 20 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 ]. Additionally, the spatial arrangement of ramets determines the reproductive success of clonal plants; this is because aggregation of ramets that belong to the same genets leads to an increased percentage of geitonogamous self-pollination [ 6 ].…”

“…However, compared with studies in laboratories or gardens, studies on resource foraging of wild plants in their natural habitats (e.g., [ 12 , 38 , 41 ]) are limited. Moreover, most of the previous studies on resource foraging of clonal plants have investigated herbaceous [ 7 , 8 , 9 , 10 , 11 , 12 , 16 , 17 , 18 , 19 , 20 , 24 , 38 , 40 , 41 , 42 , 44 , 46 , 47 ] or bamboo [ 13 , 15 ] species. The reproductive biology [ 1 , 29 , 55 , 56 , 57 , 58 , 59 ] and resultant genetic structure of populations [ 60 , 61 , 62 ] of clonal woody species have been studied intensively.…”