according to comments in the question, the actual topology is two bridges:
B1 (root) --- B2.
According to the specification (IEEE Std 802.1w-2001, sec 17.7)
Configuration Messages are transmitted if the information to be transmitted by a Designated Port changes. In addition, Designated Ports transmit Configuration Messages at regular intervals to guard against loss and
to assist in the detection of failed components (LANs, Bridges, or Bridge Ports).
That means that periodic hellos are only transmitted on designated ports, not all ports. In particular, hellos are not transmitted on root ports.
The idea is somewhat following. Both STP and RSTP track the liveliness of the "parent" node in the spanning tree (which is the root port). This is important, because if parent node fails, STP/RSTP needs to take actions to repair the tree.
Tracking liveliness of child nodes (bridges attached to designated ports) are not really important. Parent node is not doing anything if the child fails. Note, that the port is not necessary attached to a point-to-point link, and end-systems may still be reachable if the child fails. So RSTP can't turn port off and/or stop sending payload frames there.
So, in RSTP (actually similar to STP) liveliness messages are only sent from parents to children along spanning tree. In STP root sends messages and other bridges relay messages. This is because STP cannot do anything to repair topology without participation of the root node, i.e., until the topology converges with new tree build from root again. With RSTP, bridges can repair topology "more locally" - e.g., switch to alternative ports. Thus each bridge sends the liveliness individually to its "children".